Another aphorism of system administration

Here is a principle of practical system administration:

Later never comes.

Specifically, don't defer something until 'later', because it's never going to happen. Unless you are exceptionally well disciplined and lucky, either you will have lost track of things by the time you have the free time or you'll discover that any number of other bits now depend on the state of the world as it is, and it is no longer at all simple to change it.

(A surprising amount of practical system administration is about not losing track of things. Unfortunately this is not my strongest suit.)