How long do you keep it? The question behind the retention period

“Ten years” is the answer almost everyone carries around, and it is unusable twice over: in Germany it has not been true for a large share of documents since 2025, and it answers the wrong question anyway. A retention period is not a property of the paper. It is the time during which somebody is entitled to ask you for it.

So there is never only one period. For the same document several clocks run at once — a tax one, a contractual one, sometimes a commercial one — and the longest always governs. Understand that once and you need no table by heart; you can decide each new case yourself.

Ask a document four questions before you throw it away. They apply whatever country you work in; only the numbers behind them are national.

• Might a tax authority still want to see it? The longest and best-known clock. It covers everything that went into an entry, a return or a basis of assessment.
• Does a contractual claim hang on it? Warranty, guarantee, work carried out, a surety: whoever brings a claim has to evidence it — and you have to be able to fend it off.
• Could a dispute still arise from it? Unpaid invoices, contested accounts, damage not yet settled. While proceedings are live, no other date means anything.
• Is somebody entitled to demand that you delete it? Data protection law works in the opposite direction. It sets no floor, it sets a ceiling.

The first clock is the one everybody thinks of. The second and third are routinely underestimated, mostly because they are tied to events rather than calendar years. The fourth collides with the first three, which is the real reason retention needs a policy and not a rule of thumb.

In practice: you may destroy a document when the longest of the four clocks has run out. Not the most obvious one.

The commonest arithmetic error with retention is not the length but the start: periods rarely begin on the date the document itself carries.

Two starting points occur almost everywhere. Tax periods typically attach to the end of the calendar or financial year in which the document arose or the entry was made. That is a simplification in your favour: all the documents of one year expire together, which is why a year folder can be assessed in one movement. Contractual periods attach to an event — handover, acceptance, the last payment — and run separately for each transaction.

An example from German law that shows the mechanism: for an invoice issued in March 2026, the tax retention period under section 14b(1) of the VAT Act begins only at the close of calendar year 2026. Eight years later it ends on 31 December 2034, not in March 2034 — so the document sits with you for almost nine years.

The United Kingdom shows the same effect with a different anchor: HMRC's own guidance tells a self-employed person to keep records for at least five years after the 31 January submission deadline of the relevant tax year. The clock hangs on the filing date, not on the invoice.

If you settle one question in your own market, settle this one: does the period run from the year-end or from an event? The difference is, in case of doubt, a full year.

The following figures apply in Germany and nowhere else. In other markets they differ — the structure behind them, three tiers by closeness to the books, is found almost everywhere.

The eight years are new, and they are why the old rule of thumb no longer carries. The Fourth Bureaucracy Relief Act of 26 September 2024, promulgated on 29 October 2024, cut the period for accounting vouchers from ten years to eight. It took effect on 1 January 2025, for every document whose ten-year period had not already expired.

Two details that practice trips over. First: the reduction applies to vouchers, not to the books and accounts themselves — the 2026 annual accounts stay until the end of 2036, while the purchase invoice from the same year may go at the end of 2034. Second: a period is a floor, not an instruction to destroy on the day. Where another clock is still running, the document stays.

The United Kingdom as a second named example, from HMRC's own guidance: a limited company keeps its accounting records for six years from the end of the last company financial year they relate to — longer where a transaction spans several accounting periods, where equipment is expected to last more than six years, where the return was filed late, or where a compliance check has been opened. Different numbers, different anchors, the same underlying logic.

So far this has been about how long you have to keep something. The fourth clock asks how long you may — and it is why “hold on to everything just in case” is not a cautious posture but a mistake of its own.

This clock is the most agreeable part of the subject, because it is not national: within the EU the same regulation applies, the GDPR. Its principle of storage limitation (Art. 5(1)(e)) requires personal data to be kept in identifiable form only as long as the purpose requires. A document carrying a name, an address or a registration number is therefore a processing operation you need to justify.

The two clocks do not clash, they interlock: while a statutory retention duty exists, deletion is off the table — Art. 17(3)(b) GDPR carves that case out of the right to erasure. Once the duty expires, the burden reverses: you need a reason of your own to go on storing, and “might come in handy some day” is not one.

From which follows the rule that makes this section practical: the expiry of a period is an appointment, not a licence. Do nothing after eight years and from the ninth you may be breaching a rule other than the one you had in mind — which is why every period needs a written note of what gets deleted at its end.

The good news: four clocks turn into one filing routine, once three decisions are made.

Sort by year, not by subject. Tax periods end at the year-end, so one folder per year can be assessed as a whole, whereas a filing system sorted by subject forces you to handle every document separately.

Keep the event cases apart. Anything hanging on a date outside the calendar — live contracts, unpaid invoices, warranty cases, a dispute before a court — belongs in its own filing place, not in the year folder. Otherwise one matter drags a whole year past its period, or disappears along with it.

Turn it into an appointment. A point in January where you look at the oldest year folder, decide, and record what was destroyed. That record is shorter than the discussion that otherwise happens years later.

What a system can take off your hands

Documents that arise in your business system carry their date and their allocation by themselves; the period runs with the document there and does not have to be tracked. In the invoicing of Werkstattsystem, for instance, every sales invoice sits numbered and unalterable, complete with the issue date the period hangs on. What a system cannot take off your hands is deciding which of the four clocks is longest in a given case.

What the files have to be called and where they sit is covered in Digitising receipts: a filing system that still works years later.