I'd be quite worried about long term storage of important docs. I'd probably just renew it each year, but it depends on the amount of data etc.
I've got unlimited storage on Amazon drive for pictures, so I use that.
My system, documents/libraries, games and media are all on separate drives, each have daily incremental backups which are all copied to an archive external drive, and I'm about to add event based back (insertion of another external drive) for additional redundancy.
I don't work on anything super critical, but it's all aumotated and it means that if I lose a drive I can replace it very easily, and if I have to fresh wipe it has little impact as almost no data is on the system drive.
Cloud for important pics gives me peace of mind, and the freeness of prime makes it very much worth it.
Christ, long post, sorry.