My workout clothes go in the washer as I get into the shower, I find it too gross to accumulate sweated through workout clothes.

Oh. Do you know anyone with kids? We do multiple loads a day!

Exactly. I wear all-synthetic when I run or hike, because cotton will get damp and heavy and uncomfortable (potentially unsafe when hiking). I throw it in a hamper with a lid - separate from my regular one - when I'm done, and I do laundry a couple of times a week. I have shirts and smalls that I've been using nine years without a problem under this regime. One key, I think, is that I use a "color booster" (bleach alternative) specifically to eliminate the poly funk.

Doing a load of laundry for a single set of workout clothes is horrible environmentally. Even when our kid was young, it was every other day at most, and I was running more than that at the time.

I would certainly hope that nobody throws wet sweaty balled up clothes into a hamper. Got to let them dry out first. Cotton or synthetic, that is an absolute mold/odor recipe.

Put clothes in a laundry bin after use and leave it out of the way.

Do laundry weekly. Years old gym clothes will smell just fine.