Trinity makes a fantastic point; leaflets aren't for everyone.
When we moved, my partner and I did lots of leaflets and then started delivering to a few streets every day. I had lots of phonecalls/FB messages after every drop, so it worked well for me, but I was starting from scratch again.
If you're already established, could you offer a refer-a-friend incentive? Or entice your existing clients to try a treatment they don't normally have?