I think it maybe be time for a new one. What are the symptoms?

 

Slipping while in gear, moving while the clutch is pulled in. Those are some signs of a clutch going bad.

 

What does it feel like when it slips while you are riding? That may be it.

 

Drive slowly in 1st gear then upshift to third or fourth and crack the gas about halfway and hold it there. If the motor doesn't bog that bad and you feel the bike accelerating while the rpm's stay constant then your clutch is on the way out.