Sorry for the delay, got married just after the post. At our shop (and I believe this comes from dealerships and tire manufactures, ill check) an alignment CHECK is suggested every 5000 miles, I generally round it up to 6000 to coincide with the oil changes. Now that is there policies, not mine. I think cars should have alignment checked at least once a year. I see allot with the toe off, but just by a small bit. I am a perfectionist, I like my alignment numbers to be as close to specs as possible. Having a alignment shop you trust is key. I see allot of cars going to another chain and I know most of the techs set the toe and call it good. Sometimes our shop does things that piss me off, but I can only do so much and still keep a job...
I try to give advise based on what the manufactures suggest, not always what I feel.
Take care