I feel like I have the opposite. I always find that I need something I thought was transient again months later, so I have a policy of permanence. Everything gets saved/cached somewhere, and the only time it is deleted is when the cache is full.

I have a different policy of transience and that's not to use my work computer to store anything important. If it's important it should be where I can find it if my laptop takes a spill down the stairs, or by others if I win the lottery and don't show up to work one day.

I was already working toward this policy when I worked at a place where an entire batch of computers came with defective hard drives that died between 24 and 30 months of first power-on. We had 6 people rebuilding their dev environments from scratch in about a 4 month period. By the time mine died more than half the setup time was just initializing whole disk encryption. Everything else was in version control or the wiki, with turn-by-turn instructions that had been tested four times already.

The policy results in a lot of wasted effort and inefficiency.

Even secure systems like Tails have an option for persistence for that very reason.

Lack of session management is in fact annoying in the OSes, X11 protocol is generally unsupported anyway.

True persistence, however, is indeed in storing the scripts and advanced things in a backup archive, properly labelled. Sadly there is no good site to share these to reduce the unneeded effort.

Distributed archive, for that matter.