I've seen a few with a motor and drive belt. Do these survive a couple of years of continuous use?
Do any of them use a direct drive brushless motor like you would find in a mechanical hard disk? I could image something like that would last at least 5 years. Would that outlive the laser diode?
Direct drive motor would probably be the most reliable design, with quality sealed ball bearings - perhaps there's a unit touting those as features?
mikb55:
I've seen a few with a motor and drive belt. Do these survive a couple of years of continuous use?
This will depends greatly on the environment you use them in. Sunlight, dust and moisture are the mortal enemies of many mechanical, electronic and optical devices.