How to onboard clients consistently

Onboarding is the process that sets every other process

Ask a firm owner to describe how a new client is taken on and you will usually get a confident, coherent answer that takes about ninety seconds. Ask three people in the same firm the same question separately, and you will get three different answers — different order, different documents, different assumptions about who does what. Nobody is being careless. The firm has simply never written the route down, so each person has quietly invented a workable version of it, and all three versions run in parallel.

That matters more than it first appears, because onboarding is not one process among many. It is the process that determines the quality of every process downstream. What the client was told about scope becomes the argument about out-of-scope work in March. Whether the fee was recorded against every service determines whether the firm is paid for all of them. Whether the records request was framed properly at the start determines how much chasing happens in January. The data set up in week one is the data the job runs on for the next decade. Get onboarding right and the rest of the firm gets easier; get it wrong and every job carries a small permanent tax that nobody can trace back to its source.

There is a second, less obvious cost. Inconsistent onboarding is one of the main reasons a firm stays dependent on its owner. If only the owner knows how to scope a new client, price it, negotiate the awkward bit and set the expectations, then only the owner can take on clients — and growth becomes a queue behind one person’s diary. Firms trying to solve the problem described in how to make your firm less founder-dependent almost always have to fix onboarding first, because it is the point where the owner’s judgement is most heavily relied on and most easily transferred once it is written down.

The fix is not a new system and it is not a longer form. It is a single agreed route, owned stage by stage, that a new client travels whether the enquiry came to the owner, the practice manager or a junior who answered the phone.

The eight stages every new client should pass through

Onboarding fails at the joins, not in the middle of stages. Somebody sends the engagement letter and assumes somebody else is doing the identity checks; the client returns their documents and nobody notices for eleven days. Naming an owner and an output for each stage removes almost all of that, because a stage with an output either produced it or did not.

Three of those stages carry most of the value and are the ones most often skipped when the firm is busy.

• Stage 1, the written scope note. Not a form for the client — a note for the firm, written by whoever had the conversation. Half a page is enough: what the client actually needs, what they think they need, what is unusual, and what would make this client hard to serve. Almost every scope dispute later traces back to a conversation that was never written down.
• Stage 2, pricing every service separately. A blended monthly figure is easy to quote and impossible to manage. When the payroll grows or a second company appears, a firm that priced line by line can adjust one line; a firm that quoted £450 a month has to reopen the whole relationship. This is the same discipline set out in how to price advisory services.
• Stage 8, the internal handover. The person who sold the work is rarely the person who does it. Without a handover note the client repeats their circumstances to a second person in week three, which is the single most common reason a good sale becomes a poor first impression.

Give the whole sequence one target: signed to fully onboarded in fifteen working days. It is a demanding but achievable standard for a firm with templates in place, and it is measurable, which matters more than the exact number. A firm that knows its average is 34 days can work on it. A firm that has never counted will describe onboarding as “pretty quick, usually” for as long as it exists.

Worked example: what inconsistent onboarding costs a ten-person firm

The figures below are illustrative — an invented ten-person firm taking on 60 new clients a year, not a client of ours — and internal time is costed at £150 an hour for owner time and £60 an hour for staff time, consistent with the other worked examples on this site. The proportions are the point rather than the precise totals.

£23,400 a year is the visible half. Two further costs sit underneath it and are usually larger.

The first is unbilled scope. If one new client in ten has a service that was agreed in conversation and never reached the billing schedule — a second payroll, a personal tax return, a confirmation statement — then six clients a year receive work worth, say, £480 that the firm never invoices. That is £2,880 of delivered work given away annually, and because it was never recorded it recurs every year until somebody notices.

The second is delayed cash. If onboarding averages 34 days rather than 15, the first invoice on every new client goes out roughly three weeks late. On 60 clients at an average first bill of £600, that is £36,000 of billing sitting nineteen days further out than it needs to — not lost, but funded by the firm rather than by the client, every year, for no benefit to anyone.

Put together, an illustrative firm of that size is carrying something over £26,000 a year in avoidable cost plus a persistent drag on cash, entirely inside a process that everyone believes is working. That is the pattern described more generally in why busy firms aren’t always profitable: the money does not disappear in one visible event, it leaks in small amounts through a process nobody owns.

The compliance steps that cannot be improvised

Most of onboarding is a matter of good practice, where a firm can reasonably choose its own approach. Four steps are not, and they are the ones that a memory-based process drops first because they produce no immediate client benefit.

• Client due diligence, before the relationship starts. Regulation 27 of the Money Laundering Regulations 2017 requires customer due diligence measures when a business relationship is established, and regulation 30 requires the client’s identity to be verified before the relationship is established, with only a narrow exception where it is necessary not to interrupt the normal conduct of business and the risk is low. In practice that means the checks precede the work rather than catching up with it. Regulation 40 then requires the records to be kept for five years from the end of the relationship, so the filing convention matters as much as the check itself.
• A documented risk assessment for each client. Not just an identity document on file. The assessment — why this client is low, medium or high risk, and what that means for the level of diligence applied — is what a supervisory visit asks to see, and it is the part most often missing in firms that onboard from memory.
• Professional clearance. The ethical codes of the UK professional bodies require a firm to communicate with the outgoing accountant before accepting an appointment, to establish whether there is any reason not to act. Sending the letter is a two-minute task; not being able to evidence that it was sent is a finding. Send it as a numbered stage rather than as a courtesy when someone remembers.
• Authorisations, in the right form. HMRC agent authorisation is obtained through the digital handshake or a form 64-8, and Making Tax Digital for Income Tax work requires the client to be authorised through your agent services account rather than assumed from an existing authorisation. Since Making Tax Digital for Income Tax began on 6 April 2026 for sole traders and landlords with qualifying income over £50,000, an affected client who is not correctly authorised is not a paperwork problem but a missed quarterly filing.

Company clients now carry one more step that many onboarding checklists predate. Identity verification at Companies House became mandatory on 18 November 2025: a new director must verify their identity before being appointed, an existing director must confirm theirs within 14 days of the company’s confirmation statement date, and a person with significant control who is not also a director must provide their personal code within the first 14 days of their birth month. Verification can be done directly with Companies House or through a firm registered with it as an authorised corporate service provider. Whichever route your firm uses, the practical consequence for onboarding is the same: the status of a new company client’s directors is now something to establish in week one, not something to discover when a filing is rejected.

None of this argues for a heavier process. It argues for a fixed one. A checklist that a junior can run, with the MLRO reviewing rather than performing the checks, is both faster and safer than four experienced people each doing it their own way from memory — which is the general case made in how to build SOPs in an accountancy practice.

Make it hold, and what to do this week

Writing the process is the easy half. Firms have onboarding documents in shared folders that nobody has opened since the day they were written. What makes a route stick is that it lives where the work lives and that somebody notices when it stalls.

• Put it in the practice-management system, not a document. Onboarding should be a job type with the eight stages as its stages, so a half-onboarded client appears on a list rather than sitting invisibly in somebody’s inbox. If your system cannot do that, the requirement belongs in your selection criteria — see how to choose practice-management software.
• Template everything that is templatable. Engagement letters, the records request, the welcome email, the professional clearance letter, the internal handover note. Anything rewritten from scratch each time will be rewritten differently each time.
• Review onboarding in progress once a week. Sixty seconds in the existing team meeting: which clients are mid-onboarding, which stage each is at, which one has not moved. This is the mechanism described in how to run an operating review, applied to the one process where delay is least visible.
• Measure two numbers. Average days from signed to fully onboarded, and the proportion of new clients that reach stage 8 within fifteen working days. Both are cheap to count and neither can be argued with.
• Ask the last five new clients. One question — what was confusing or slower than you expected? — will find the gaps faster than any internal review, because clients experience the joins that the firm cannot see.

To start this week: take the last three clients you onboarded and reconstruct, honestly, what actually happened to each — what was sent, by whom, in what order, and how long it took end to end. The variation between the three is your real process. Then write the eight stages on one page, give each an owner and an output, and run the very next new client through it exactly as written, changing it where it turns out to be wrong. One deliberate pass produces a better process than a month of designing one in the abstract.

Firms that do this consistently find the benefit arrives somewhere they were not looking. Onboarding stops being an owner task, which means the firm can take on clients at the rate it wins them rather than at the rate one person can process them. That is the operating capacity discussed in how to increase capacity without hiring, and it is exactly the kind of work sequenced in the Optivo method and run month by month as part of the Optivo Monthly COO.