When the 7x17 got mothballed over a decade ago I had a few boxes of film to put aside. In an ideal world these would go in a freezer. The next best place would be a fridge. I didn't have either of these to spare so I had to improvise and hope...
The boxes were sealed in bin liners to reduce the risks of dust, damp, mold and light. Then wrapped in sheets and towels to help maintain a reasonably consistent temperature and popped in a box in the coolest room in the house. Over the intervening years this was then typically used as a clothes horse and covered in daily detritus of life as is the usual way.
The first film to try after the Ritter 7x17 was restored to use was the slowest and most likely to be in a usable state, some Era 100. This has seemed to have survived nicely. No apparent loss of speed and no emulsion damage. I'm not that great at metering, or very consistent in developing but the negatives have looked great and no obvious fogging.
Most of the rest of the film I have is Ilford HP5 plus which is ISO 400 and the most likely to have seen a drop in speed and/or an increase in fogging. If these had deteriorated badly I would need to stock up again so it needed testing.