I spend my first 40 epochs trying to max out invitation rewards. I was educating, reminding 1 day before validation, reminding 1h before validation ... even begging not to waste my invitation. Nothing helped me to exceed 20% success rate. Now I don't care. I'm not inviting anyone. I just grab unused invitation rewards. Especially now, when price is stable and network is not growing. When price will pump, mining reward will pump too, people will take care about mining more than now so they will care more about not wasting m invitations. Thats when I'll come back to send them.