Some lenders will allow you a "rolling late". Here is an example of how this works:

Suppose your late in January, then Feburary, and then March. The lender says that since they are all back to back to back its considered a "rolling late". This means that even though you were late 3 times the lender only counts it as 1. You cannot have more then a string of 6 lates in row. So 7 30 day lates in a row would count as 2.

Mortgage lates are late payments that are at least 30 days late. However, your mortgage company will probably charge a late fee if you are more than a certain number of days late, usually 10 or 15 days.

Mortgage lates are one of the most important factors a lender will look at when deciding on whether or not to approve a new loan. Often someone with no mortgage lates and a lower FICO credit score can get a better interest rate than someone who has a higher score but does have mortgage lates on their credit history. For this reason always try to pay your mortgage before any other bills - it will put you in a much better position when you need to refinance or purchase a new home.