i broke a few belts because of pulley alignment issues. didnt even seem like they were misaligned until i really got to looking at them. spent some time making sure the belts ride in teh center of all pulleys and wheels and its been good since
as for the bearings there is a pretty simple fix, youll need to get some fiber washers from home depot ot where ever. they will be in the hardware section with the nuts and bolts
heres what you need
just replace the washers in the bearings with those fiber washers