Mostly, they don't roost. Mostly, they just get discarded. Years and years of accumulation of things that were important once but aren't any more. Stacks of 1.2 MB 5.25 inch floppies, backed up using hardware and software that we no longer have. (Fortunately containing information that we no longer need.) Bernoulli cartridges the size of a comic book and half an inch thick that held an astounding 10 MB of data. 10 year old release versions of software written in an obscure interpreted language.
I saved less than a tenth of the stack as being interesting or of possible value. The rest is going out in the trash. And the trash collector won't be happy about it...