Originally Posted by HillRider
Allan wrenches, either the L-shaped type or those mounted in screwdriver handles, tend to round off after some use and then do real damage to the screws they are used on. This is a particular true with the small ones like 4 and 5 mm. Buy new good quality frequently which will reduce this type of problem.
+1. Then be sure to throw the old, worn one away. Resist the temptation to keep it as a spare.