Other than arranging for a direct debit for the balance due, I am not taking responsibilities for arranging for payment of client estimated taxes.   I tried it a number of years ago, and two payments were not made, never received an error message, so now, I do not agree to take on the responsibility.   

For a lot of older taxpayers, they prefer to write a check.   They have been do so for many years and trying to get everyone to make online payments is challenging for this group.   I understand, many younger taxpayers do not even have checks anymore.