One thing that bothers me is they never seem to be low on ammo. And Daryl's bow is such a waste as it takes him at least 30 seconds to reload. My weapon of course would Michonne's samurai.
I always assumed the times they are out on their supply runs, It includes ammo. With all the empty businesses/bldgs around, it doesn't seem like they'll run out soon as long as they can travel to different places.
TIS