If you are only looking at a life expectancy of 2-3 years then just buy the DUI 400G and be done with it. If you don't launder it EVERY time you wear it (and you won't need to) it will easily last that long, especially if you aren't using it every weekend.
Some tips to help keep extend life and keep it from getting too funky:
1. Store it in doors (NOT the garage). You live in Florida, the Type B Thinsulate is a wax coated fiber. If it gets hot, the wax coating starts to degrade and the fibers will separate, leaving you with "dead" spots.
2. Store it flat, NOT hanging. Again, the weight of the suit itself will elave you with dead spots near the shoulders if it spends lots of time on a hanger. The quilting helps, but this will still happen.
3. After use turn it inside out and let it air out. You can also sprinkle it with a little baking soda and let it sit for a couple of days then shake it out real good (or vacuum it). I know people who also used Febreeze, but I was leery of using any sort of unknown chemicals on it.
4. When you do have to wash it, use cold water, gentle cycle, and NO SOAP. If you can soak it in a bathtub, even better. Let it dry flat.
5. Use a base layer.