If the material is boxcloth, braided leather, or cloth, there is very minimal tension so the straps should remain at the same tension when you are standing as to when you are sitting. Set the length that you find most comfortable standing, sitting, and bending. You should be able to determine this within 10-20 minutes of wearing the braces.
If the material is elastic then there can be anywhere from minimal to super-stretch tension in the straps. If your pants are bobbing up and down every time you move, then the elastic could be worn out and you will need a new pair. If your braces are too tight and do not provide sufficient stretch when you bend down, you should loosen the straps. Firm suspender straps can cause stiffness in your shoulders, so be careful when wearing a new pair of elastic braces.
Generally, the wider the braces strap, the stiffer the tension, and the narrower the strap, the more stretch will be in the strap.
Avoid super-stretchy suspender straps, like these...
To find what works for you, try a few different brace materials (elastic, boxcloth, leather). Wear them for a day to determine their comfort and feel. You may discover that you prefer boxcloth over elastic straps.
- How do you find the tension in your braces/suspenders?
- Do you find your pants ride up by wearing braces?
Note: all photos are used solely for non-commercial use and to illustrate braces in fashion. No plagiarism is intended.