I would be more conserned with the laser motor wearing out. That is what killed my Dreamcast. The laser was fine but the motor to move it just gave up from too much use.
What do you use to lubricate them? I've got a few PS2s that are starting to give occasional disc read errors and a little laser maintenance might be overdue
White lithium grease for the rails (but don't get it on anything plastic), silicone grease for the plastic gears, and sewing machine oil for the motors :)