Getting dressed or undressed can be a challenge for those with functional limitations. Shoe horns can help with getting shoes on and there are special devices to help those who even have trouble pulling on socks. My must have was a buttoner and zipper device with a thick non-slip handle that would be easy for me to grasp given my lack of finger/hand coordination, strength and dexterity.
The hook end slips through the hold of zippers when pinching it isn't a realistic possibility and handle provides a little leverage for pulling it up or down. Yes, elastic waist bands are the best, but sometimes a girl (or boy) just wants to wear her favorite shorts or jeans.
As for the buttoner end, slide it through a shirt or pant button hole and loop it over the button. Then pull it through the hole with a little guidance from your other hand. Again, the handle provides some extra leverage for those who need it.
For those who only need the buttoner, another option is comes from Good Grips. And, as I've addressed in a prior post, there is also the Magnetic Button that works well for dress shirts and other small buttons.
If you have used anything to overcome one of your dressing functional limitations, please share it with others in the comments.