I've sent my entire professional life singing the virtues of writing everything down for later use. Think of it as an instrument control logbook if you will.

If you do everything right wrt your mining rig, then you shouldn't have so much as a hiccup for the first 3-6-perhaps 9 months. However, when you do have that hiccup (external events can and do happen out of the blue) - you will have forgotten the most basic setup decisions that you made months prior.

Did you write a *.sh file to start your miner; did you need to make a fine adjustment - hell, what's the root password to the computer. All of these things will be forgotten memories when you need them and if you don't want to burn hours recreating your rig - please write everything down.

Personally, I'm a bit old school and for the really important 'stuff' I use a nice notebook - making sure that I create a workable table of contents (along with a thousand post-it notes).

Just my two bits…

EDIT: I see a lot of folks mentioning passwords, please understand I used passwords as an example only for illustrative purposes. And yeah, you should use a password management system to gen/store these (e.g. last pass, 1password, roboform, etc…) I'm talking more about the need to write down what you've done on your rig to Decrease troubleshooting time months down the line.