Numbers I check before merging

I used to add a layer of abstraction the first time I saw a pattern repeat. Now I wait for the third. The waiting is uncomfortable, but the abstractions that survive that wait tend to last.

I trust monorepos more in the second year than I did in the first. Most of the early friction goes away once the tooling catches up.

The fastest debugging trick I've learned is to write out, in one sentence, what the system is supposed to be doing. Half the time I notice the bug while writing the sentence.

If a config file has more than a dozen options, half of them aren't being used. The other half are being used in ways the original author didn't predict.

When a system surprises me, my first instinct used to be to fix the surprise. Now my first instinct is to figure out which mental model of mine was wrong, and update that.

Most of the trouble I see in production comes from boundary cases someone promised would never happen. The code is fine. The plan is fine. The promise is what ages badly.