Yes, one binder might be enough (we totally understand), but a few smaller binders make it easier to tote key binders around with you to appointments. Organized on the counter with the help of a dish organizer.
Good idea if you have rock solid ground that is hard to dig up. If you don't cover the holes you can use them for herbs & annuals. also lined with weed barrier cloth & used rebar in several places for stability. It makes maintenence super easy.