There are no rules for inspiration, you have to have a quality view on things and my curiosity helps me to find inspiration in the most unconnected of strange situations. But there is no rule, or only one: Keep your eyes open.
If you spend your time waiting for the inspiration to come to you, for the ideas to “gush forth”, it will be too late. It is like with magazines: there is a deadline…we have deadlines and that is a healthy form of discipline. it creates ideas.