On a four-day backpacking trip a couple summers ago, I made the mistake of budgeting exactly zero plan for hygiene and by day three my tentmate had started leaving space between us at the fire like I was radioactive. Jumping in the freezing lake wasn't cutting it, and I genuinely considered cutting the trip short over how gross I felt.
Back home I compared a gravity-bag solar shower against one of these rechargeable pump versions with a friend who camps way more than I do, and she was adamant the pump style was worth the extra weight because you don't need direct sun or gravity height to make it work.
Took it on the next trip, dunked the pump in a stream, and had an actual warm-ish rinse in about ten minutes without needing to hang anything from a tree branch. My tentmate has stopped flinching when I sit down next to the fire, which I'm counting as a win.
