Buying a torque screwdriver won't allow to provide a professional or safe service & if you think buying a torque screwdriver will help you become perfect at the job then God help you.
Give it a couple of years & they'll no doubt change their minds and say they shouldn't be used.
Why won't it help me to provide a safer and professional service? It's a way of accurately and consistently measuring whats happening. If not for my own security and peace of mind but for any circumstances where a discrepancy may occur and proof of quality of work is required.