Hey Koko!
We don't have an in-app warning as of now, but we do currently send email warnings if you're close to your limit. Example attached!
As Chad mentioned, the testing feature is a good idea to get a sense of how one or two leads look.
Another option is, depending on how your Lindy looks, you can 'limit' the amount of loops that your Lindy runs through so it will only do X amt as to not run through so many credits!
What is your use case here? Happy to provide some guidance!