I wear jeans most of the time I'm not in my BDU's. Majority of jeans came from American Eagle. I have about a 32 waist, but some clothing makers 30's will fit, but the Dickies I wear when I'm workin my second job fit me best in 34, so I can't ever tell.
One neat trick I picked up along the way to save time when shopping for pants is to take a pair off the rack, and with the button buttoned, wrap the waistband around your neck, the two ends should barely touch at the back of your neck, and you'll be in the neighborhood for the right waist size, it's saved me some time not having to try on too many different sizes.
I change my pistol choice/carry method, to go with what I feel like wearing, it goes like this:
Jeans: Para-Ord P-13.45 IWB in my Threat Solutions UCR (Ultra Concealment Rig) with my Glock G26 on my ankle in a Galco Ankle Glove.
Casual Khakis: same as jeans
Dress Pants: Just the G26 on the ankle
Dickies: I put the G26 in my DeSantis Nemesis pocket holster, yeah it prints, but I figure when I've got a Para-Ord, an ASP baton, cuffs, OC spray, and a radio on my duty belt, people aren't really going to notice the bulge in my pocket.
The only way I can retain flexibility in my wardrobe, is to have flexibility in my firearm choice/carry method. I like flexibility in my wardrobe. YMMV