[strken]

All the rules of thumb seem to have massive categories of exceptions where they don't work, and that makes me suspicious of applying new ones that I don't fully understand.

DRY up your code... unless the two code paths look similar but aren't the same.

YAGNI... unless "it" is a database backup, a load balancer, or test coverage of your signup flow.

KISS... unless your problem is complicated enough that a simple solution only implements half of what you need.

Microservices are great... if you've got more than one team and can support the operational overhead of SDN and service discovery. Monoliths are great... until you're pushing code to them every minute and they become impossible to refactor.

etc.

[mgkimsal]

and yeah, you should be suspicious of doing anything that you don't understand. this is all knowledge work, and there's some implicit notion that when you make a decision you have some level of understanding. the bigger the potential impact, the more understanding you should have.