One big shed, almost always. Two smaller buildings means two deliveries, two footprints on your property, and two separate spaces that don't connect. Organizing your stuff across two buildings gets old fast.
One bigger shed gives you more usable square footage per dollar, better layout options, and one spot where everything lives. You can set up zones inside instead of splitting things between buildings. The only time two smaller sheds makes sense is if you have two very different uses, like one for lawn equipment and one as a workshop on the opposite side of the property, or if your site can't accommodate a single larger footprint.
