- writing the self-assessment part of a performance review at the end of a quarter
- help your boss make a clear, specific case for you to be promoted, and not rely on their distractable memory
- updating your resume/LinkedIn when the time comes
- reminding yourself that you have been competent and gotten stuff done before, if you're feeling frustrated or having a bad day
I just have a Google Doc called "Accomplishments" that I'll add things to every so often, including any kudos or compliments that I receive from co-workers. I'll also write up a short description of a project I worked on that succinctly describes why that project matters to the business and what was hard (and therefore impressive) about my part of it.
Example:
Trace Store Service Integration
Migrate from directly accessing databases through ActiveRecord to using a Thrift service instead, enabling our Data Services team to change storage backends without disruption to our end users.
Team size: 2
Don't forget to check if someone would still ask "so what?" at the end of your writeup!