I have found two similar sayings in English which say: undertake only what you have the money or ability to do and no more. But apparantly they work only in British English, whilst I need something more epidemic and in common use in both Americans and Britons.
- Cut your coat according to your cloth. (UK)
- As long as your blanket you may stretch. (Perhaps a translation from another language)
What do the Americans say in the same sense? What is the most common way yo say it in both AmE and BrE?