What I keep forgetting about timeouts

Caches solve a problem and create three new ones: invalidation, observability, and the slow drift between what the cache thinks is true and what the source thinks is true.

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.

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

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.