So here's another issue that seems more common for me now I'm older/overweight. Maybe its the weight that's driving it. And that is having trousers which fit at the waist when I sit, and then fall down when I stand. The ONLY options I can think of involve elastic, either in a belt or stitched into the back of the waistband.
In today's RTW trousers I was holding the trousers up surreptiously with a hand in the pocket so I could walk about, not a good look I have to say.
I also seem to bloat a bit at certain times of the month, and during the day (ie skinner in am, fatter in pm).
I have some RTW trousers I bought in 6 colours which I wear a lot for work. They have a partially elasticated waist and the older ones also have belt loops and a skinny belt.
As a fix I am planning on adding elastic within the back of the contour waist on at least 2 pairs of trousers.
Hopefully I can do it in a not too obvious way but still have comfort and not have to hold my trousers up. When I was younger I would alter the trousers in the centre back waist to fit neatly, these days I need a bit of give.
What I tend to do is....
Where trousers have a contour waist (many of mine do), open up a little of the stitching on the inside of the waist facing near the side seams.
Insert a length of elastic running from the left side seam to the right side seam through the back waist.
Stitch in the ditch at the side seams from the right side to secure the elastic.
Restitch the facing from the right side.
Particularly at the back I do still have a significant waist, so this snugs things in there (avoiding back gapeosis) whilst still allowing me some give when I need it.
Hurrah for (partial) elastic waists!