Upload & Sell: Off
I wear a suit (or most of it) at every wedding. I bring the jacket but don't wear it in the summer months. Sometime I'll wear the jacket during ceremonies, but only if there's air conditioning. No A/C, no jacket. I do wear the shirt and tie (loosened) throughout the day.
As far as "investing" goes, I have yet to pay more than $90 for a nice wedding suit. I have a closet full of designers (Ralph Lauren, Louis Rafael, Hilfiger, etc.) that I picked up pretty cheaply from places like Marshall's and TJMaxx. Marshall's tends to have a better selection and a larger variety of sizes.