Got the big set of bellows from ARC on my bridgeport, not fitted them just dropped them over the back.
impressions, keeps a load of crap off the ways but because they have not been cut and fitted stuff still get in at the corners.
My fault needs to be fitted correctly and it would stop that.
They are wearing well except for steel chips sticking to the bellows, not as bad as it sounds as they do brush off and are not buring thru but I do use this machine in anger, it's a paying workhorse and big cuts with decent inserted cutters are the norm.
Light cuts with steel brush off as does alloy etc. In a home shop I suspect the life span is a fair few years, in my industrial shop probably two years and they will start looking tatty.
Hope this is a truthful answer.