I most certainly do not do it myself - that would be a surefire recipe for falling off the roof and breaking my neck! We have it done probably every two years or so. We have ivy growing up our house and that needs to be cut back fairly frequently so the gutters get cleaned at the same time.
We have our gutters cleaned when we notice water splashing out of them, but we'll clean the gutters of the shed ourselves. It's a flat roof so it's not as dangerous as cleaning the gutters on the house.