I don't think I could write without revision - anyway some always comes in because I write first in longhand then type it into the computer while I can still remember what it says. There have been so many occasions when I've said "no, that doesn't work at all" and if I'd gone any further there would have been masses of wasted work.

No offence to the people who told you to do that, but it sounds a bit "painting by numbers" to me. Surely what counts is how much useful stuff has been produced at the end of the time, not arbitrary figures on the way through? I think you are very sensible to go with what works for you - "Thou Shalt Not Tamper with a Working Program".