Transport mechanism maximum "life".

6 years on avg. for the sony's. Playing time is the key. Actual spinning of the disc. there's truly no hard and fast rules but it's always 'SPINNING TIME'... and not just turned on time. Keeping the ambient temp constant can allow for continuous energizing of the component without trouble.

When the laser does weaken, and it will with much, much use, another can be installled. the whole of the CDP doesn't have to be thrown out. I just did my CDP's drive/lasers (SACD/CD) at an authorized service center for under $300. After about 100 hrs. of playing/spinning... it sounds like a new player.

It's about hours of use not years of ownership.

Depending, really, how much you use it. Mine, using the machine daily 5-6 hours, had to replace after 5 years.

I suspect that many last longer, and the manufacturer is informing you of what they find to typically be the case. If yours has not yet failed I wouldn't worry about it.