Never be a borrower or a lender
In reality this isn't always possible, and yes I've had to borrow on occasion in the past when it has been really necessary, but I'm now 37 and aside from my student loan I'm completely debt free. I own my own home outright - I finished paying off my last personal loan this summer. It's like a huge weight off my shoulders.
I've never had a credit card, and I have no intention of ever getting any more loans (like I say with the exception of student loan.)