I don't use a dress form, but I have a friend who sews a lot of clothes who tried a commercially made one, and was disappointed with it. Even with a dress form adjusted to match your measurements, it may not match your shape very closely. Most dress forms resemble a slender 20-something with excellent posture, a flat stomach and strong shoulders, so a dress form may not match some parts of a person's body, such a bit of a tummy bulge, sloping shoulders, or some spine curvature. You can adjust the form somewhat, by pinning or taping on padding to match a tummy bulge, say. My friend sews closely fitted garments, so she was much happier with the
duct-tape dress form she made, as that ended truly matching *her* shape, not a generic one.
Now, if the clothes you are making are not very closely fitted, a commercial dress form may work well enough for your needs. I do suggest looking critically at how its shape compares with yours when you get it - taking some pictures of both it and yourself (front, back, each side) and comparing them can be helpful. See if you can use some padding in appropriate spots to get a closer match. Then, try on some of the best fitting garments you have, and see how they hang on yourself and the dress form.