Wear what you want. I've been into watches for a long time and it's my experience that unless it's someone who knows your into watches, 99.99% of people won't notice your watch, much less care if it "goes" with a suit or jeans!
As as far as not wearing your Gen as a daily wearer, why? That's what it's for, it wants to be worn! I personally would never own a watch, rep or gen that I was afraid to wear! My .02
Edit. I do make choices on which watch I'm going to wear based on planned activity, won't wear my GS or gen Omega or Rolexs, etc while building a new deck or working on car. Never based on clothes though.
and by the way, unless your buying very exotic, rare pieces, watches are a horrible investment! If your looking for an investment, your much better off with a good mutual fund or something similar. Your Rolex will hold its value better than most, but that's it. Rolex produces and sell about 1,000,000 watches a year, impossible for them to all go up in value!