If you wear modern microfiber base layer next to your skin, it will keep you comfy & not build up body odors.
They dry very quick. If you don't like the idea of washing them in the sink, well then...
Just wear them into the shower, soap up a bit, rinse, and strip in the shower to finish.
Wring em & hang em to dry.
But since they don't build up odors, you won't really have to wash em unless u want too.
Here is how I tell when it's time to wash my shirt....
https://vimeo.com/m/90922220