Don't wait for a clutch to slip before doing something. Clutch pedal free play should be 3/4 to 1 1/2 in. If it's excessive, the clutch may not fully disengage, causing grinding and damage to the transmission. If it's too little, the clutch disc and throwout bearing take extra punishment. If your car has a conventional clutch linkage, refer to a repair manual for the way to turn the adjuster to reset the clearance. Also, lubricate the metal pivots of the clutch linkage with chassis grease, the plastic parts with silicone grease.

Although many clutches are self adjusting, they have tooth-pawel plastic adjusters that should periodically be lubed (on the pivot and the teeth) with silicone grease.

Many self-adjusting clutches require that you periodically lift the clutch pedal up an inch or so to do the adjusting which isn't actually self-adjusting in our book, but a darn sight better than having to crawl under the car with a flashlight and a wrench.

Hydraulic clutches may require not only a mechanical rod adjustment, but may also need topping up of fluid in the master cylinder, and perhaps even bleeding. Replacing the hydraulics fluid in the clutch system should be done when you change brake fluid, since it's common for both systems to use the same type of fluid.