Everywhere, sort of... The company I work for prints on/embroiders all sorts of bags and occasionally they'll sell the rejected stuff to the employees for a buck or less so I have bags for obedience, agility, scootering, tracking and going to Grandma's/traveling. Each has whatever leash/collar/harness is required and anything else needed for that activity. Makes it a lot easier to just grab whatever bag is necessary out of the closet before heading out the door.
I also have bags to store dog winter coats/sweaters, my safety stuff (orange vests/reflective gear, flashing lights, lighted collars/leashes) for night walking - no street lights/sidewalks around us, first aid stuff, and miscellaneous things that seem to accumulate.
Dog food is kept in bins in the kitchen, treats/medications in a cupboard next to the bins, treats on the counter by the kitchen door, leash/collar on a peg by the door, under the counter overhang. Toys are optimistically kept in a cloth bin in the living room but are usually underfoot all over the place.