Why my CI got 4 minutes faster

The team I learned the most from didn't have great tools. They had a great habit of reading each other's pull requests in full, including the parts that weren't theirs.

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.

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.

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.