Credit: what is defined as a "late payment". 

A late payment is "any payment received past its due date".  Late payments are also classified into these categories: 30 days late, 60 days late, 90 days late, 120 days late, etc.  - I think you get the idea. If you as a buyer, are considering applying for a mortgage, late payments on a credit report will have an impact on what interest rate you may receive and whether or not a mortgage loan will even be granted to you.

Late payments have an affect on credit scoring, too. The good news is, you can always change the past with good behavior. If you find yourself in a credit crisis, several late payments, with feelings like you can never be made whole...there is hope. Once you can get back on your feet, begin making payments on time, the past credit crisis will slowly disappear if you stay on track. The more time that passes, the less the affect on your credit score & credit portfolio.

There is a saying in lending, you only have to worry about the past 7 years (unless a bankruptcy, judgments or tax liens are involved).