Do you charge major purchases without thinking much about it? As in, "If I don't get it on credit, I'll never get it"?
Let's think about that for a moment. Where's the money coming from to pay back the loan? Out of your pocket, right? So, if you can pay for it, you can pay for it.
The key is paying for the item first instead of last.
When you make payments to your savings account in anticipation of buying something you want or need, the interest involved is yours, but when you make payments to a loan or credit card company, the interest involved is theirs.
Pay the money first - before you get the item, instead of last, after you've got the item, and the interest you save is your own.