I've recently started DMing a lvl16 DnD 3.5 party. While I have some general knowledge of the rules mostly I just wing it. Fake it till you make it. That is why I really appreciate it when I have some players that can correct me when I go overboard. I really need the help, especially when casting is concerned. Spells are relatively complicated for me. To be honest I think rules lawyers are relatively young players who aim to be the best/most powerful characters that they can be. While older players tend to be more rules relaxed aka as long as it fits the story line almost anything goes.

I try to avoid situations that are rules heavy and focus more on the roleplaying part with the occasional listen, spot, diplomacy checks. In an 3 hour session we might role two to three times. However next session I will surprise them with an annoyed green dragon, surprise will be relative since we have a divine oracle in the group. To test the combat capabilities of the group. Many players switched characters.