Of all the work in a monthly handover this is the part that actually takes the evening. The statements come down in a few minutes each, and then you spend two hours trying to find a document for forty small payments, most of which you recognise and none of which you can prove.
It goes faster once you know that your receipts are in three quite different places, and that only one of those places is your email.
Your inbox has the receipts from suppliers who send them, which is most one-off purchases and a good share of the recurring ones. They are searchable, they are sitting there, and this is the easy third.
Billing portals have the ones from suppliers who never email you anything. Hosting, cloud, domains, and a lot of software subscriptions work this way: the card gets charged, you get a one-line notification or nothing at all, and the actual invoice is filed in the billing section of an account you have to log into. Every one of these is a separate login, and in the closes we have run these are consistently the expensive ones, because each supplier costs a few minutes of remembering which email address you signed up with.
Paper is the rest. Taxis, lunches, hardware bought in a shop, parking. Whether this is a small problem or a miserable one depends entirely on whether you photographed them at the time.
Open the bank and card statements for the period and work down them line by line, finding the document for each line as you reach it. Every line you attach something to is finished, and what is left on the statement is exactly what you still have to hunt for.
Starting from the receipts instead is the natural thing to do and it is what makes this feel endless, because a pile of forty found receipts tells you nothing about whether there were forty-three payments. You also cannot tell, halfway through, how much is left.
A useful side effect is that you notice the lines nobody can identify while you still remember the month, rather than three weeks later when your accountant asks about a forty-euro charge to a company name that means nothing to either of you.
There will be a few. Some payments never had a document, which is normal for bank charges and card fees and for moving money between the company's own accounts. Others had one and it is gone.
Write the situation on the line either way. A line that says "no invoice, monthly account fee" is settled and a blank one is a question your accountant has to send you an email about, and that email will arrive at the point where you have stopped thinking about the month entirely.
The wider checklist this belongs to, covering statements and invoices out as well as receipts, is what your accountant needs from you each month.
Clerk.AI does this pass for you on your Mac. It reads the statement, searches your email for the matching receipts, signs into the billing portals that only hand invoices over behind a login, reads the receipts in your photo library, and comes back to you with the lines it could not settle rather than with all of them.
Runs on your Mac. Pay what you decide, including nothing.