I've had a direct debit going to the taxman for 3 years now,.. in Ireland there are some stupid rules that go along with it,.. eg Any money I've paid in since the end of the last financial year (Approx €2500) can't be used against last years tax bill,.. only against this years. EG,.. they have my money, near 2 years worth at the moment, but they won't let me use all of it against my tax bill for last year.
Despite that,.. I personally find it reduces stress at this time of year and wouldn't go back to all that saving up for the "big bill".