Sidecars and the things they hide

Most retry logic I've removed turned out to be hiding a real bug. The retries made the failure invisible, and the bug compounded for months in the background.

I split a 4000-line file into 12 smaller ones this week. The smaller files weren't actually easier to understand. The 4000-line file was a problem of structure, not of length.

Latency budgets work better than latency targets. Targets are aspirational. Budgets force you to delete features when you go over.

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.

There's a kind of premature optimization that comes from imagining a future team. "What if someone needs to swap this out?" Often, no one does.