depends on your driving style, and how much you abuse the clutch/transmission. If all the gears are rough on engagement then yes you mave have a clutch situation on your hands. However grinding a single gear consistantly isn't really an indicator of a failing clutch more of an internal transmission problem. If you're "racing" and dropping from 5th down to 3rd or 4th alot then you may have abused synchro's a bit to much for that gear set. Don't tell me it can't be done because I know of a certain person who has bought an ITR swapped EK hatch and within the 3rd week of owning it he had torn out 3rd gear for the most part.

I've got the habit of rev matching and "heel-toe shifting" on down shifts which makes things easier on the transmission. But to each his own.