Eaxactly this..
I know loads of builders, and you never make many out of them, just day work, why i've never really bothered.
i've stopped pricing for one builder as i hardly get any jobs i price, found out after he was getting me to price say a kitchen reskim and putting like £400 on top of my price and then getting someone cheaper from the pub to do it, then ringing me up to put right..no wonder i was never getting jobs, putting 800 pound or so on top of my price on a render, i don't mind people making money off me, but as far as i'm concerned if someones making money off you they should pay you when u finish if a small job, not wait 30 days.....
And the jobs he did send my way he always wanted a drink out of it, how can you price in a drink on skimming an artex ceiling, lol...on a bigger job maybe!