Unless kept clean the pulleys become hard to move and will not go the
full range. Depending on what you turn and sand, humidity, and other
shop conditions this can be rather frequent. Also, this drive system
can drift out of parallel too easily for my taste. When I'm in my
shop, I want to work on wood, not machine maintenence. Once aligned
and set up perfectly, a machine shouldn't need additional
set-up/alignment work more than once in about 10 years (unless it's
abused). BTW I wouldn't consider 150 hours to be heavy use. That's
not even the break in period.