There is no better time than now for your best ideas. Use them, there will be more. Don’t save them for a better project or a better client because good ideas breed more good ideas.
When we become stingy with our concepts we get attached to them and when we get attached to an idea it becomes the thing that is always pushed to another day because we think it has to be perfect. It's easy to put off the perfect idea because it'll take too much time.
Additionally, the more things you try the more likely you’ll find something that works and when you do find something that works don't be afraid to repeat yourself.
You don't have to reinvent yourself on every project. And repetition is the thing that all your favorite artists are known for. Repetition is style and style is the thing that reputations are built upon.