A finance lead once walked me through an approval chain that required two signatures on any contract above $50,000. I asked where the threshold came from. She said she'd inherited it. The person before her had inherited it too.
We eventually traced it to a deal that went badly four years earlier. Someone signed something that turned out to be expensive, and the response was a second signature above a dollar figure that felt roughly right at the time. Since then the company had built out a robust legal function, added contract review before signature, and moved average deal size well past $50,000. The condition that produced the rule was gone. The rule was still running on about 40% of their deals, adding nine days to each one.
Nobody in that chain was being careless. Everyone was doing exactly their job.
Companies preserve decisions and lose the reasoning behind them. The rule is easy to encode. It goes in a policy doc, a workflow, a required field in the CRM. The reasoning lives somewhere much less durable. In the head of whoever made the call. In a Slack thread from 2022. In a hallway conversation that never got written down anywhere.
So the rule travels forward and the reasoning doesn't. A few years later you have a company full of controls nobody can explain.
That gap shows up in two ways, and they look like opposites.
The first is accretion. Nothing gets removed, because nobody can prove it's safe to remove. Any given rule might be holding weight. So it all stays, the operating model gets heavier every year, and people quietly route around the parts that stopped fitting.
The second is the correction. A new leader arrives, sees obvious bloat, and clears it out. Some of what they remove is residue. Some of it was load-bearing. They find out which was which about six months later, usually during an incident.
Both come from the same missing information. If you don't know why something exists, you can't tell whether it still should.
The fix isn't more documentation. Most companies already have more documentation than anyone reads. It's a change in what gets written down.
"Two approvals required above $50,000" is a rule. No expiry, no conditions.
"Two approvals required above $50,000 because we have no legal review before signature, and the last unreviewed deal cost us $400,000" is the same rule carrying its own audit. The day legal review exists, the sentence stops holding together. Someone reading it will notice.
Write down the condition, not just the conclusion. Then the rule can tell you when it's finished.
Most of this gets lost in transitions. Someone leaves, someone new takes over the function, and the handover covers what to do without ever covering why any of it was decided. The rules survive the turnover fine. The reasoning walks out with the person who had it, and nobody thinks to ask them for it on the way out.