No, it is not required to add lubrication after installation. Perhaps in a few years.
Unknown how it is held on, but appears to be pretty solid. No movement or play on the bearing. I suspect the bearing is pressed onto the shaft.
If you have 4 in stem rollers, these should work just fine.
Check homedepot.com to see if in stock near you. Otherwise order online.
I saw the 2 previous answers but they are all wrong ... The DLR13 is better than this one (DLR6200Z) because the cycles for the DLR13 is 150,000 cyc for 250 lbs door and 250,000 cyc for 150 lbs door ... This DLR6200Z has rated only 100,000 cyc .... The 2 are having the same price ...
The 6200ZZ bearing has a lifetime guarantee* and is rated for 125,000 plus door cycles for a 100 pound door (12.5x greater than the standard DASMA requirement for garage door rollers). http://www.duralifthardware.com/home-2/products/rollers/ultralifemax/
Nylon rollers, steel ball bearings, and steel shaft.
These rollers are produced in China with strict quality standards to meet and exceed door manufacturer requirements.
Each of these Ultra-Life rollers have 100,000 cycles ... The 10,000 cycles is applied only to other rollers ... They are just using the cycles to compare between Ultra-Life rollers to the other rollers ...
Believe these are online only!