About a month ago, I picked up a KHS Urban-X, which is an ideal bike for my commute. It uses quick-release skewers for the wheels. I was perusing the manual, and noticed a section about the skewers, mentioning it was really easy to over or under tighten them. It recommended taking the bike to a shop every time the skewers are removed, to ensure they're properly refitted.

To me, this seems to defeat the purpose of quick-release wheels. I'm wondering if skewers really are that sensitive/difficult to reinstall properly. My basic point is that, in the event of a flat, I'll have to remove and reinstall them, and want to know what I'm getting into.