It's most definitely worth doing a 2x charge when your developing your biz, firstly you'll get minimum drop out so your customer base is not only growing but is stable, secondly, it promotes confidence in customers that you know what your talking about and come across experienced, thirdly your not picking up dross who will drop you on the next clean, and if they do you've at least been paid for your time.
Only now I reluctantly do first cleans at normal prices because I can absorb the low rate a little more now than I could, we had 28 new cleans on Tuesday, the hourly rate was poor, but the volume the canvasser is bringing work in offsets this in the long run ( I hope ) but I hate it !!
Darran