DoomE.Q.

Riding the clutch is when you keep your foot on the clutch pedal even when it's not being depressed. This disengages the clutch just a little bit and eats the clutch up at a faster rate. Either that or they are referring to you declutching too much. Just keep off that pedal unless you're shifting up or
down.

-DE

turboy

Riding the clutch refers to the practice of holding your car in place (say on a hill/grade) by partially (or sporatically) engaging the clutch (vs using the brake) to keep from rolling backwards. Most often you see people doing this at stop lights to "hold" their car in place. Obviously, very bad for wear on the clutch plate. Another bad habit is having the clutch disengaged (pedal down) for longish periods (while waiting for a light to change, etc.). This causes additional wear (not though severe) on the "throwout" bearing. Generally it's a good practice to put the car in neutral and release the clutch pedal when ever stopped (with the engine running).

narrus

Yeah, I haven't posted much if ever here but, a fully depressed clutch is fine. It's the halfway part that kills it. Granted, you might as well just drop it into neutral at a stop light, no reason to wear out that leg.

Also the person saying it could be refering to letting the clutch out excessively slow, which burns it up too. Generally happens when you are either learning to drive a stick since you are trying not to stall.