Months behind, a couple of years behind, or a file nobody has opened since the last accountant asked for it. It is more common than you think and it is a defined piece of work, not an open-ended problem.
Nobody wants to open a file that is eighteen months behind, so it stays closed. Meanwhile deadlines pass, the accountant keeps asking, and you have no reliable picture of what the business is actually doing.
A file that reconciles, outstanding periods able to be dealt with, and a starting point for either doing it yourself properly or handing it over for good.
Jumping around a behind file is how people end up doing the same month twice. The order matters more than the speed.
Usually the last completed BAS period or the last year the accountant signed off. Everything before that is settled; everything after is the job.
How many accounts, how many periods, how much source documentation actually exists. This is what the quote is built on, and it is why we look at the file first.
Each period reconciled and closed before the next one starts, so a fix never has to be applied twice.
Transactions nobody can identify get collected into a single list. You answer them in one sitting rather than fielding messages for three weeks.
Reconciled, with the outstanding periods ready to deal with and a clear note of anything still unresolved.
Is it too far gone? Almost never. Missing source documents make it slower, not impossible, and there are reasonable ways to deal with genuine gaps.
Will I get a lecture? No. Behind is the normal starting point for this work.
What if I do not have all the receipts? Say so up front. It changes the approach, not the answer.
Catch-up work is a one-off job with an end point. Most people who go through it once do not want to repeat it, which is usually where ongoing bookkeeping comes in.
The two are quoted separately so you can decide on the ongoing arrangement after the backlog is cleared, not as a condition of getting it cleared.