You cant beat the personal face to face contact.....whether commercial cleaning, domestic, carpet cleaning etc etc
People who ring around for prices are looking for the cheapest price normally, and will call around till they get it.
Genuine people will welcome you to come to their homes / places of work etc and you will be able to charge accordingly, as you will have turned up smartly dressed and dealing in a professional manner.
Why be happy with a 20 - 30% success rate??
I wouldnt, as it is a waste of time for me. The individual face to face approach generally brought in for me a 90 - 95% success rate....you work out the maths compared to 20 - 30%??
Phone calls always have their place as a start of contact, but would never give prices out on the phone.....as Mike said on his comment above, that personal contact should give you a higher conversion rate and to be better paying, plus you will see exactly what needs to be cleaned, plus you will see potential problem areas.....which you can utilise to make more money for you.....If you think you are a good enough cleaner that is.....
Regards
Tim