For much of my sewing life, I placed my faith in the patternmakers, a slim, pretty standard fit body - and a lot of luck.
These days, with a rather different shaped body, a lot of patterns designed for the 'average' woman - and a huge stash to use up, I have come more and more to rely on toiles.
Not your couture type toile, just an old bit of fabric to test size, techniques and style, but it makes such a difference. Things fit better and I don't waste my 'nice' fabric on something unsuitable.
The latest sacrifice to the toile stash is an old duvet cover, but I also have lots of cheap sheets, upholstery weight fabric, and remnants of various stretch fabrics.
Also, I don't do anything fancy with the toile - usually it isn't a 'wearable' toile, and just sew as much as I need to. Sometimes - like the camisole I recently made, they are suitable to wear in the garden, but, sometimes they will be re-used for other things or used for ironing cloths, and test scraps.
Sometimes it's just a way of avoiding making an expensive mistake for me, and avoiding a style which will not suit me.
Jessie