You do understand how the estimated tax works, don't you? It doesn't mean you must "file taxes four times a year" by any stretch of the imagination; when filing for tax year Y, you estimate what your tax burden will be for year Y+1 and pay that in four installments quarterly during year Y+1. You then file Y+1 normally at the start of Y+2 and either get a refund (you estimated too high) or pay additional taxes (plus a penalty if your estimation was significantly low). Fundmentally little difference from payroll withholding.