A short guide to data retention

This is one of those topics that looks small until it costs you something. Everything we would tell a client about data retention in the time it takes to drink a coffee.

Data outlives the applications built on top of it, which is why the model deserves more thought than the screens. It is the sort of thing that looks like polish right up until it costs you an enquiry.

What is actually at stake

Keeping everything forever is a liability, not an asset. None of that requires a large budget, only a decision and someone to own it. Most teams find the first pass takes an afternoon and the maintenance takes minutes a month.

The practical version

Retention rules should be written down and enforced automatically. The cost of getting this wrong is rarely visible on the day it happens. Most teams find the first pass takes an afternoon and the maintenance takes minutes a month.

Where it usually goes wrong

Deletion has to work across backups too. There is a version of this that is over-engineered, and it is worth avoiding. Anything you cannot measure here, you are deciding by taste, which is fine as long as everyone knows it.

The short version

Numbers get quoted in meetings long after anyone remembers how they were calculated. Three things worth confirming about data retention before you move on:

• Someone can say what the current setup is without going to look
• Retention rules should be written down and enforced automatically — and you know whether that is true here
• There is a way to tell whether the last change to this helped

The point is not perfection, it is knowing which of these you have consciously chosen to skip.