I've found from perso - a good friend - that the adjustable waist band slacks are great for office/dress wear. The problem is that if you wear, say, a 32 and then stick a small double stack 9 with good holster in, the pants need to be 2" bigger. If you remove the gun - not allowed, office drawer or home safe - then you may suffer from a droopy waist band and the consequential constant pulling up. At that point suspenders start looking like a solution. With the expandable waist, it takes up some slack, you might take up a notch, done.
Or worse, the old physique tapers as it descends from waistline to knees, and there is nothing to stop your clothing in it's long and inexorable attraction to ground zero. Adding another 40-60 oz is no help at all. At least with a good belt and slacks that cooperate, you get the best of both. There are now a lot of dress stretch belts, albeit too narrow and which are also part of the growing mens market. Hint.
It also goes to the holster - thin materials follow contours, and we have gotten into a situation where holsters are considered quality if they are handboned sufficiently to read the markings on the slide. Take a look - all those creases and folds may have originally been for retention in the day, but now are contrary to our intent to conceal. We are requiring an OWB look at me styling feature with a concealed hide me please holster. If you can see the slide markings thru the material, maybe it's the wrong holster?
Just sayin ; )
There is also the cut of the pants, and a stretch material while comfortable in jeans defeats concealment to a degree when its cut to a close fit. Or, at least, thats what she said. For marketing reasons men prefer the illusion of being fit as a 32 year old international jet setting spy, (stirred not shaken) when the reality is some of us could use a pair of pants that fit a little looser. Not that anyone needs to wear them like Pappy O'Daniel - but that was a fashion statement in the day. LIke, 1938. Aren't we pushing it with hip hugger pants and skinny legs in over 50 wear? Duluth did offer "contour cut" jeans at one time, I'm thinking all mine look like that after 6 months. It seems mens wear is dominated by youth fashion, and we blindly follow along.
When Concealed Carry in no flash states became a thing tuckable IWB got started, and folks were also tossing their suitcoats on the back of the chair in offices because HVAC got better, too. For those who can wear IWB, go for it. For those of us who have well insulated abs, it's a different game.