When I used to do A LOT of sewing, for others as well as myself, I had a posh 'adjustable' one. It was very useful indeed - especially for that seemingly-most-simple of things, hemlines. I sold it when I gave up my business, then when I was only sewing for myself, I made - with the help of a friend - a 'body double' out of clingfilm, ducttape and expanding foam filler. Great fun to make! If you mount it on the base of an old adjustable office chair it's even better. Then dress it in your old clotges inc a floor length skirt, stick a balloon in its neck and a scarf or shawl over its 'head' and you can give folks a fright!
The finished 'item' was a bit annoying as it wasn't as pinnable as the commercial one, and I had to handle it more carefully, but its likeness to me was uncanny especially in odd places like the shoulders, so excellent to see how things hung on me instead of on the hanger.