How long do sanding discs generally last?

The life of your sanding discs can also depend on which tool they're used in conjunction with. For example, they can wear down much quicker when using an orbital sander because of the increased pressure.

Sanding discs can last longer with the right maintenance, which includes cleaning off any debris that has been attached to them. This can be done by soaking the disc in water and using a steel brush to remove it from the sandpaper.