Hey … it may be a silly question… but here goes anyway… over time … say 5 years of regular riding does the comfortability of uni seat deteriorate ? How often do you folks replace your Uni saddles / seats ? Have noticed my comfort level recently dropping. oh and to uni community… do stay safe out there. …
Cheers Jimmy
In some seats, the foam does tear or change shape, so that may be what you are experiencing. Also, seat bases can brake (the metal part in them), and suddenly feel weird. For Flatland, where you are grabbing the seat a lot at the sides, I replace the seat every few years (I have a carbon base, so only foam and cover), usually because either the cover is tearing, or the foam is breaking.
Thanx for weighing in Finnspin. I swapped my 29” uni seat (less used). And noticed added comfort straight away. Both seats are same Kris Holms fusion. Which proves the saddle does wear out over time. … if anyone else out there getting uncomfortable in the saddle … then probably a sign to replace … cheers Jimmy
Back in the day (1979-83) Schwinn unis would sometimes experience deterioration of the foam insert in the saddle. They were very user-serviceable saddles, with a single-piece foam insert and a thick vinyl/plastic cover that could be removed/replaced without tools. Steel base sat on top of what most people today think of a Kris Holm mount/ That was originally the Schwinn spec. Anyway, the foam would just start crumbling away. You’d look inside the cover to see a much smaller piece of foam in there! 
I’ve never seen anything close to that with more recent saddles, though they can probably do the things mentioned earlier, as well as possibly loose their “air”, in that they don’t compress as much as they used to.