edited

I have another idea about limits, that is a storage limit, put a maximum of 400 energy that you can save (3 refreshes x120 and a little more), for who want sim a lot of nodes at same time, from then appears a warning message saying that to buy more refreshes or to get more free energy is needed spend the current energy. This is an easy way to prevent hoarding.

Anyway would be needed put restrictions in the other things, the participation in raids, the daily rewards and the initial free crystals.