shelves & cupboards on rollers
My shed is less multi-purpose than it was supposed to be - however, I've done one thing 'right'. That is, to make a sub-frame (I work mostly in wood) and set up the shelves atop them; wheels beneath (one set of turning wheels only). I did this originally so I could access almost never-used rolladoors easily when needed.
The first time I did this was for a second-hand cupboard (sliding doors are slightly better, less than you'd think). Later, I got some metal frame (100kg per shelf) shelves and did the same for them. Tip - hardwood under-frame. Or metal. I also clad them in plywood and gave them a lock - keeps honest people out.