Income mix
Charities rarely fail because of a single bad year. They fail because one relationship ended and there was nothing behind it.
Mapping income by source and identifying concentration is the starting point of any income strategy. It is also what a funder looks at: a charity dependent on one funder is a risk to the next one.
The goal is not maximum diversity but conscious risk. See mapping your income and reserves policy — concentration is one of the risks reserves exist to cover.