The beauty of the manual loading trays is that they don't wear out. The internal mechanism guiding the laser will though. Probably the optical unit itself will wear out first though. I would advise anyone just now buying a unit to purchase extra optical units. They can be found on Ebay and such, and there are Youtube videos showing how to replace.
By the way, I am not suggesting that these Transports and DACs in the $5,000.00 range are equal in quality or performance to the units costing 2-5 times more.