Proper roller lubrication: Rollers should be lubed no more than twice a year. You can find the proper spray lube at any retail hardware store. If you have rollers with ball bearings than the bearings and the entire inside of the door track should also be lubed no matter what kind of rollers you have. The biggest mistake homeowners make is over lubricate the rollers and track because they think the noise has to be the rollers. And they will use heavy grease to lube them.

rollers need lubrication on several occasions

If a roller needs lubrication and is the source of squeaking than a quick spray of lube will fix the problem right away, when you over lubricate you are just making a big mess and attracting dirt and sand to stick to the grease. Also grease will eventually drip down on cars and items in your garage. If you live in a coastal region where the salt air rusts metal very quickly then you should spray lube on all metal parts of your garage door to slow down the rusting process. In fact you should lube all moving parts on your garage door.

ball bearings rollers

Some garage door rollers do not need constant lubrication. These rollers do not have ball bearings and the wheel part of the roller is made entirely of plastic. These rollers do not rust so they are desirable for doors in coastal regions where rusting rollers can be a constant problem. They are not that strong so I would not use them on heavy garage doors made of wood. The heavier wood doors can put too much weight on a plastic roller and break it off. If you lubed plastic rollers every couple of years it would be enough. Too much lube will attract dirt and sand to the roller causing it to deteriorate sooner than normal.