Tubs

If glued properly tubular tyres should stay put longterm... I've certainly never heard otherwise, nor had an issue with tyres coming loose over time, .

Actually... yes.. with time--- especially when used in both rain and sun---- the mastic can get dry and brittle--- just like other cements. When one suspects that the tires are no longer properly glued one just needs to let the air out and check... its pretty easy.. If the tire is not well cemented it'll be very easy to remove and there will be a bunch or dried and flaked cement "dust"... Wire brush.. fresh cement and ... Another thing to watch out for is not the rim cement BUT the base tape cement. I've seen quite a few tires whose basetapes were no longer well cemented.. Some tire brands seem to be worse and some better..