The easiest thing you can do to take care of a Luger is keep a snap cap in the magazine that is in the gun. The most delicate and most common part to break on a Luger is the toggle hold open lever. Keeping a snap cap in the mag keeps the pressure of the follower off the lever.

She isn't as sexy as a numbers matching, with finely strawed parts, pre WWII gun, but I shoot it any time I feel like it, and never feel guilty about it.