Better to save hearts or spend them?

I am waiting. There could be a 3rd option with them releasing more items to buy. But if nothing new comes along I will probably buy some trees to add some color. We still have 25 days to go and I already have bought all the items and still have 300 hearts remaining. And I am not even trying to collect more, they just keep coming between friends. There just has to be more, otherwise this was just too easy.