More and more components are coming that have explicit torque settings in the instructions. Due to the OP's experience - and many, many others - with stripping bolts, I have come to highly recommend that even the experienced bike-mechanics out there invest in torque-wrenches. The Park Tools TW-1 & TW-2 are relatively inexpensive, and quite accurate. Cheaper than the aggravation of stripping the threads out of a brand-new derailleur or a Thomson stem.