The casters on my office chair were really starting to bug me. They were seeming to get stuck or have a hard time rotating, etc. We had just replaced the old ones which were worn out. It got to the point where my husband was going to try gluing the shafts in the chair bottoms, but we didn't know if that would work with plastic.
I did some online checking and found out that we could just wrap some electrical tape (shiny kind) around the caster shaft a couple of times and then insert them back into the chair bottom. So far, no more issues! A cheap fix it for an otherwise still usable chair.
Source: http://www.needcasters.com/how-to-snug-caster-sockets.htm
By Marti S. from Athens, GA