I've been running MT32/XCMS tires since 1994 (roughly). The tread lasts a while and keeps on grabbing. The tread actually outlasts the sidewalls. That's why I gave it only 4 stars for durability. My friends have the same problems with the XCMS and the MT16. BUT, these are the best tires on the market for what we do here in Hawai‘i. That is why we tolerate the susceptible sidewalls.
Conservatively, I get a good 30-40 hours of tight trail riding abuse out each back tire, probably more. This is not bad at all for a back tire of a trail bike.