This can not be overstated.....we have been extremely fortunate to hit a stream of "gold" that has taken us from one trade to the next, and, keeping them "fed and watered" when on site, paying on the day the invoice is presented has perhaps helped to ensure that as well as recommending the next trade to us, they are happy to vouch for working with us, even though we can be very definite ("picky") about what we want.
Sparing his blushes @Benpointer has written an excellent blog, and is a masterclass in keeping trades on track with excellent outcomes.
So true, but on a Friday make it 3pm!