I want to cover the interior walls of a shiplap wooden shed with plywood to hang tools and put up shelves on a flat wall. Do I need to insulate the gap between the plywood and the wooden planks of the exterior of the shed? The floor of the shed has plenty of gaps and the door isn't tight. Moisture will get in regardless. It is going to remain a toolshed.
I have read that it is needed only if you plan on heating or cooling the shed to keep the temperature consistent. I do not plan on this.
I feel like any moisture that got into the cavity would dry up as the shiplap planks on the outside are not airtight so a moisture build up shouldn't happen but maybe I am wrong. Would a cheap win win, be to put a water-resistant barrier in the cavity so the moisture will never hit the plywood if it does get through the shiplap?