I guess people get tired of hearing about riding around on older bikes, but since this is the commuter forum, I can say it again.

I find that when you ride a bike every day in urban areas, you go through at least one rim/wheel per year. Since you need your bike every day to get around, you need a couple of spare wheels on hand to make a quick switch. Since you are a heavier rider, you will go through a lot of rims - especially rear rims/wheels.

Keep your eyes open for older bikes with spare wheels you can canabalize or at least try to pick up a spare set of wheels.