I’ve just started playing clicker heroes. Currently I have three heroes; Cid (level 24), Treebeast (level 12) and Ivan (level 7). I’m not following any strategy as such rn, just clicking the monsters and buying the heroes randomly.

What I wanted to ask was, do you guys prefer buying new heroes or upgrading the existing ones? Also, upto what level should you upgrade a hero to before going for a new one?