Less than 10 times..... I don't really have any slow payers anymore. I had one last year and I collected 8 months worth of 10% late fees with the help of a lawyers letterhead. The late fees alone were as much as the original bill.
It is stated on every bill!
ALL PAST DUE ACCOUNTS ARE RESPONSIBLE FOR 10% SERVICE CHARGE PER MONTH PLUS COST OF COLLECTION INCLUDING ATTORNEY FEES
Its more of a scare tactic than anything else and I will let people slide for a reasonable time frame such as 10 - 20 days over the 30 on my commercial accounts. All of my residential is COD. They have never paid a late fee.
Great if you can get it. Here the late fee is limited to 2.5% per month(30% per year) by law. Only ones that have found a way around that are the pawnshops and the Payday loan shops. They average 500% or so. lol