How often should you use door hangers to get the best results for your service business?

It's always more effective to leave 4 door hangers on 250 homes than to leave 1000 door hangers once. We try doing "5 around" so the two houses next to our client and the 3 across the street. It also helps to have a different kind of door hanger each time hitting different pain points or highlighting a different offer, just because someone said no to you the first time doesn't mean they'll say no to something related to what you originally offered them.