I still give them ES vouchers and envelopes to stuff with their checks…  if they want to pay electronically, I stick with direct pay

Our problem with sending estimates by check: Virginia no longer accepts checks over $1500 per quarter, mandating electronic payments on its website that's not user-friendly. New York's Dept of Revenue online somehow does not "recognize" the (correct) taxpayer information. The Direct Pay at IRS.gov was super-easy when I tried it. I also fill out SSA vouchers for clients to withhold taxes (max allowed at 22%). I suggest year-end RMD distributions with heavy withholding. My elderly clients are having difficulty remembering estimated payments. With interest rates for underpayment now higher (8% IRS 10% Virginia) estimated payments will be important this season.

For those who want to schedule payments, we use EFTPS. For those who won't or don't want to or have an extra payment need (such as a buy/sell of some sort), we use Direct Pay.

@Greta   The Ad Hoc Committee to Oppose Year-End RMD will be holding its annual meeting on December 29, to commemorate all the taxpayers who took the advice of waiting until year end -- and then died, or had a stroke or heart attack, or lapsed into dementia in the last couple months of the year.  

Without these self-imposed procrastinators, our work would be less and our fees would be lower.