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Guide

How long to keep a firm's client documents

The legal deadlines for a client's invoices, accounting records and labour documents, and what to do when the SAT asks for one you can't find anymore.

Published September 14, 2026 · Updated September 14, 2026

The short answer

A client's accounting records and CFDI invoices are kept for five years, counted from when the return they belong to was filed, not from the document's own date. A company's founding records (incorporation, capital, mergers) are kept as long as the company exists. Labour documents are kept for the last year of employment, plus one more.

That figure is the easy part. What actually costs a firm isn't memorizing five years: it's that the deadline runs at the same time for thirty or a hundred clients, across folders from different years, and when the SAT asks for a specific client's March 2023 CFDI, the question isn't "can I delete it now?": it's "which folder did it end up in?".

The real problem

It's not the number, it's finding it

Five years fits in one sentence, and every accountant knows it by heart. What a firm hasn't solved is the other part: five years of invoices for every client, added up, is thousands of XML files, hundreds of bank statements, and a folder structure that changed at least once in that time.

The SAT doesn't ask for "the 2023 books." It asks for one specific CFDI, from one specific client, from one specific month, and gives you a short window to hand it over. That's the moment the legal deadline stops being the problem — you already knew you had to keep it — and the problem becomes where it ended up.

With one client, any folder works. With thirty or a hundred, and years piling up, the challenge stops being fiscal and becomes organizational: two different things this guide keeps apart on purpose.

The deadlines

How long to keep each type of document

Seven rows, three different laws. No figure here moved because an AI chat said so: the source is always the law, cited by article.

Retention periods for a client's documents, by type, legal basis and starting point
Document typeRetention periodLegal basisStarting point
CFDI invoices, bank statements and general accounting records5 yearsCFF, art. 30From when the related tax return was filed (or should have been filed)
Articles of incorporation, capital increase/decrease minutes, merger, spin-off and liquidation recordsAs long as the company existsCFF, art. 30From when the record was drawn up
Documentation backing a tax loss the client is still offsettingThe whole period it can still be offset, plus 5 more yearsCFF, art. 30From when the loss was generated
What the SAT can audit for a client (its power to review)5 years; 10 if the client never registered with the RFC, kept no accounting records, or never filed the annual return while required toCFF, art. 67From when the return was filed or should have been filed
Individual employment contracts of the client's staffFor as long as the employment lasts, plus 1 yearLFT, art. 804(I)From when the employment relationship ends
Payroll records, attendance logs, and receipts for profit-sharing, vacation pay, Christmas bonus and social-security contributionsThe last year of employment, plus 1 more yearLFT, art. 804(II–IV)From when the employment relationship ends
Personal data on clients or their employees that no longer serves your privacy notice's stated purposeMust be cancelled (blocked, then erased), unless another law requires keeping it longerLFPDPPP, art. 11Once it's no longer needed for that purpose

The tax deadline and the data-protection one can clash: a CFDI stops serving your client's privacy notice long before it hits the five years the SAT asks for. When that happens, the law that requires keeping it wins, LFPDPPP art. 11 already says so, which is exactly what CFF art. 30 does with accounting records.

What trips people up

Two cases the table alone doesn't explain

01

When the SAT can reach back ten years

The normal window for a SAT audit is five years, but it stretches to ten when the client never registered with the RFC, kept no accounting records, or never filed the annual return while required to (CFF, art. 67). Keeping only five years "just in case" doesn't cover these three cases.

If any of the three happened to a client in a given fiscal year, that specific year stays open to review for a decade, not five. It's worth flagging those years in the client's folder instead of assuming every year runs on the same clock.

02

When the client is carrying forward tax losses

A tax loss the client is still offsetting extends how long you keep the papers behind it: you keep them for the whole period the offset right exists, plus five more years after it's used up (CFF, art. 30).

It's the exception people miss most because it has no fixed lifetime date: it depends on when the client finishes using the loss, and only whoever keeps their annual return up to date knows that.

Before you say it can be deleted

Seven things to check

None of them needs a lawyer. They're questions the table above, or the client's file, already answers.

  1. Confirm you have the CFDI's XML, not just the PDF

    The XML is the full tax receipt; a PDF without its XML proves nothing to the SAT.

  2. Count the five years from the tax return, not from the invoice date

    A January invoice's clock starts when the return for its fiscal year was filed, which is normally months later.

  3. Set the company's founding records aside in a folder nobody touches

    Articles of incorporation, capital changes, mergers, spin-offs: kept as long as the company exists, not five years.

  4. Flag the years a client's books or filings fell short

    Those years stay open to audit for up to ten years, not five.

  5. If a client is offsetting tax losses, file that documentation separately

    It runs on its own clock: as long as the offset right exists, plus five years.

  6. Keep labour documents separate from tax documents

    They fall under a different law (LFT) with a shorter clock: the last year of employment, plus one.

  7. Before deleting for privacy reasons, check whether the tax deadline still applies

    Personal data gets cancelled once it no longer serves the privacy notice, but if the CFDI holding it is still inside its five fiscal years, tax law wins.

Where Wurz comes in

Wurz doesn't set deadlines, it helps you find the document

When the SAT asks for a specific client's March 2023 CFDI, Wurz doesn't decide whether you can delete it,the table above does that. It handles the other half of the problem: it organizes thousands of CFDI and bank statements by client and by period, and when you ask, it tells you which document has the answer, with the exact citation so you can check it yourself.

That doesn't replace your backup. The documents keep living in your Drive, Dropbox or OneDrive, Wurz isn't where your only copy lives, and keeping them for as long as the law requires stays your responsibility to the SAT, with or without Wurz in the picture.

What Wurz does not do, so there's no confusion: it doesn't set deadlines, doesn't interpret the law, and doesn't replace your backup. It finds and cites what you already have saved; how long to keep it is the table above's job, not Wurz's.

If you don't have a folder per client and period yet, start with how to organize each client's documents: this guide's deadlines are easier to apply on top of that structure.

And if what worries you is where your files sit while you keep them, that's covered separately in security.

See how Wurz worksSee the plans

Common questions

What people ask most about this

How many years must I keep a client's invoices?

Five years, counted from when the tax return that invoice belongs to was filed (or should have been filed) — not from the CFDI's own date (Código Fiscal de la Federación, art. 30). If the invoice backs a tax loss the client is still offsetting, the deadline extends: it lasts as long as the offset right exists, plus five more years.

How long should a firm keep its clients' tax documents?

The general rule under CFF art. 30 is five years for accounting records and tax documentation, counted from the related return. Some documents fall outside that rule and are kept longer: articles of incorporation and records of capital changes, mergers or spin-offs are kept as long as the company exists, no matter how many years go by.

What happens if the SAT asks for a document I already deleted?

It depends on whether the legal deadline had already passed. If the SAT asks for a CFDI from three years ago and your client's books were in order, that document should still have been kept — the deadline is five years, or ten if the client never registered with the RFC, kept no accounting records, or never filed its annual return (CFF, art. 67) — and not having it is something to sort out with your client and their legal counsel, not with this guide. If the deadline had genuinely passed and the document no longer had to be kept, there's no fault to report.

How long do I keep a client's full accounting records, not just their invoices?

The same five-year rule in CFF art. 30 covers the full accounting record — journal entries, trial balances, working papers — not just CFDI invoices. The exception is documents that, by their nature, don't expire while the company exists: articles of incorporation and records of capital changes, mergers and spin-offs.

Are a client's employees' labour documents kept for the same period as invoices?

No, they follow their own deadline under a different law. Individual employment contracts are kept for as long as the employment lasts plus one year (Ley Federal del Trabajo, art. 804(I)); payroll records, attendance logs, and receipts for profit-sharing, vacation pay and Christmas bonus are kept for the last year of employment plus one more (same article, sections II–IV). These are shorter windows than the five tax years, and they run separately.

Try it with your real documents

Upload a handful of receipts from your most demanding client and ask the question that normally takes you half an hour. That's how you'll know if it's worth it.

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