The simple shower squeegee. Probably costs a few dollars? I don't know; I got mine for free from my local Buy Nothing group. In our second shower, we use an old window squeegee that I bought at the Dollar Store years ago. For a dollar. We unscrewed the wooden handle that came on it, and just never use the spongy side. You can probably buy one that is actually attractive if you are willing to spend a couple dollars.
They both conveniently reside in their respective hanging shower caddies, so they're easy to grab right after we bathe. In our tiled shower, using the squeegee is totally straightforward: just swipe in long strokes from the top of the wetness (it's about shoulder height for us) to the tub rim, then swipe the water off the rim of the tub. It should all roll right into the tub where it will go down the drain instead of turning your grout black with mold. Work from one side of the shower to the other; the squeegee should leave it pretty much dry as you go. It's very satisfying when you think about never having to scrub your shower again.
In our vinyl shower, it's a little trickier because there are rounded corners that need to be squeegeed side-to-side, rather than vertically. If you have this kind, just start at the top and work your way down. Then sit back, enjoy your clean showers and all that sweet free time.
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