I suppose it depends on what you're riding. Myself, just day rides usually not over 5 hrs (I'm older.. that's about all I'm good for) & I just wear the same bibs/jersey I use on the road. During summer month I often carry a 3rd bottle in the center bottle, taking up a lot of space that could otherwise hold a 2nd tube (I run tubeless, but...), extra food, a back-up pocket pump, etc. I've been considering a handle-bar bag for over-flow stuff so that I'm not food or hydration limited while up in very remote areas. I like to pack enough stuff (canisters, a back-up bump, small tools, back-up hanger, chain quick-links) where help is nonexistent. I probably need to carry more 1st aid stuff than I do - which is nothing.

I could not imagine carrying anything in cargo shorts - I would think that would chafe while riding but could be wrong.