Office Chair on Carpet.

Get a standing desk.

 

Buy one of those plastic chair matts.

 

If you don't want to use a mat you might consider doing a corner of the room, or whatever area the desk/chair occupy, in something like pergo. Looks nice, hard to damage. Sucks to have to tear out a section of fresh carpet but better looking than a mat and better than rolling around on carpet.

If you're not using chairs with casters it may not matter.

 

I think most people get one of those acrylic chair mats. Don't forget to move it now and then to vacuum underneath so your carpet doesn't get permanently matted. I was sold on this particular model by the fourth bullet point...

 

Make a mat out of spare carpet?

 

Those caster glides are not strong enough and acrylic mats make dents on the mat and carpet. I think your best best is to get a spare carpet or buy a cheap thick small rug.

 

Get a nice wooden chair mat.

 

Get a few of those and you can have a roller skating rink.

 

that's been my solution. I tried plastic mats but found that residential grade carpet didn't really offer enough support for the plastic

 

I used the plastic mats before and our carpet was too plush, so the mat would sink down whenever I sat in the chair. I'm thinking that wooden mat looks nice...