I'm not a big fan of technical documentation on code except where absoultely necessary. What's worse that having no documentatino is having misleading and outdated documentation, especially when you can't ask the author anymore.
To reduce the bus factor, and just because it's good coding, I recommend:
automate all tasks that are done frequently and can be reasonably automated (for manual steps, have the automated one write them out)
unit tests and integration tests of course
small branches, so in worst case you lose only a bit of work
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I'm not a big fan of technical documentation on code except where absoultely necessary. What's worse that having no documentatino is having misleading and outdated documentation, especially when you can't ask the author anymore.
To reduce the bus factor, and just because it's good coding, I recommend: