I'm planning to build a 6' x 8' utility shed for my wife. This will be a simple sloped-roof, 2x4 framed shed, sheathed with 1/2" plywood, with 3/4" treated plywood flooring. I have seen several suggestions for setting the base of the shed, from placing the corners of the rim joists on concrete blocks (which are leveled on a bed of sand) to pouring concrete pillars to the frost line depth and anchoring to that. What is truly needed to ensure stability over time? Thanks in advance for your advice on this.