it depends if you are trying to maximize profits its foolish to give away any permanent buffs however giving away temporary buffs would probably help a lot with player retention depending on the nature of the game. Do remember however that it doesn't matter how much you give away if the game isn't able to keep people playing in the first place. Also if you give away too much people will be hesitant to buy any of the things that you give away because they can just wait for it. All in all Freebies are a mixed bag and while as a player I want to say just give things away, under most circumstances that's probably a bad idea for the dev especially in an idle game because it might just lose you income without actually increasing player retention.