Evan;

So this old guy visits his wife's doctor, twist his arm up over his head and complains "Hey doc it really hurts when I do this". Doc looks at him, replies "then stop doing that", and that will be $30 for your insurance co-pay.

#1 Simplist explanation is; Cross chaining while pedalling hard will f&%* up your bikes, no matter how many of them you buy. It is not the bike's fault nor the LBS guys fault. Read all the posts here that are saying "don't do cross chaining". Then move to #2.

#2) I would suspect that your local shops are going to start charging you a lot more money for each repair action than they charge other folks or start refusing to work on your bikes at all. It is probably time for you to start by learning what all the main parts of a bike are called by name and then begin to learn how each of them are installed and adjusted, what tools are required, etc. There is just a mega-boat load of information readily available for the reading on the internet, on the Park Tools website, on Sheldon's website, on Youtube, etc. Also learn to use google. Take lots of notes. Fill your head with useful information and your hands with tools...

3) Goal is to not wreck your bike bits by mis-using/abusing them and to be able to fix your own bikes when they wear or break. You should be able to start saving serious money also.