You don't need to do it that frequently if you don't want to!
Buckwheat hulls can easily last 5 years without maintenance. Still, I prefer the wool alternative, which again doesn't need to be cleaned often or at all, as most people do with their regular mattresses.
The fact that stuff is washable is an advantage for me, because I'm a bit allergic, and regular mattresses don't have a simple way to be deeply cleaned. The best thing you can do so far is to vacuum them with a Dyson for mattresses.
