I actually normally put either 2 kinds of washing stuff in my travel kits these days.

Some bio-degradable soap for the hikes, so I can get away with having just 1 spare-shirt and some undies in my hiking-bag.

Regular powder in a double zipper bag (that I can open up and close again, since they always pick it out at airports, which is also the reason I always put it in hand-luggage) for any trips to Africa and Arabic countries. The presence of machines and infrastructure is spotty at best and not to be trusted anyway.

But other than that I love the laundry room I have here (shared between tenants), but I know a lot of people around Sweden that have their laundry-machine sitting in their little bathrooms with a regular pretty sink (for make-up & tooth-brushing and the likes) next to it.