Switch from cotton to (Merino) wool, at least for shirts. It doesn't absorb sweat and then start to smell, so you can wear it many more days before washing (and you can just hand wash in the sink, easy). They also breathe well, work great as a base layer, and feel extremely soft. It'll cost you $80-100 for a t-shirt, but I've found it worth the investment. I've gone from rotating through like 15 Uniqlo tees to only wearing a couple shirts. And you can do the same with pants and even socks.