It's easy to strip out a Phillips screw, especially if you belong to the “more torque is better” club. Rather than mangle the screw head and then have to drill it out, try these tricks.
At the first sign of “slippage,” coat your Phillips screwdriver tip with valve grinding compound (sold at any auto parts store). Then try removing the screw (Photo 1). If that doesn't work, buy a handheld impact screwdriver (sold at auto parts store). Smack the screwdriver with a hammer (Photo 2). The “shock and turn” motion usually frees up the screw.