Delegate liberally
The main reason to delegate liberally is related to culture building.
Many people think of delegation as a way to help leaders avoid burnout and distraction. While you do want to make sure you are able to focus on the things that matter without being distracted by things that don’t matter as much (at least in the sense of you doing them), there is a better reason to delegate.
The main reason to delegate liberally is related to culture building: The more things that other people are responsible for, the more they will feel ownership and buy-in.
Almost nothing is too small to be delegated. Many people will feel valued just owning something, even if it is small. And it is very difficult to not take pride in a team or project to which one has contributed.
You should also delegate big things, and you should be more cautious with those. “Big” is mostly relating to the impact of the thing. If the impact is small, delegate away with very little thought. If the impact is big, you should still find ways to delegate, but be intentional with who you delegate to.