Mine last and last too. I rarely change a blade and it is usually due to a nick caused by those darn errant pins. I dont do a lot of layers and if doing a Buggy Barn technique with 8 or more layers, I change a blade.
A good mat is critical and I found out that some fabric with poly or other fibers can actually dull blades. I almost ruined a rug hooking cutter blade with some mixed content wool.