It's like any other job, you just guess what materials and labor it takes to do it. Normally on a reface you don't remake the faceframes but recover them with veneer because the sides of the cabinets need to be refaced also. I like to use phenolic veneer (formica back) to reface cabinets. You don't have to be as fussy fixing damage to the cabinets to veneer over with that type veneer. On the average kitchen, I figure a days labor to take the doors down and re-veneer the cabinets and another day to sand it and finish them. Then the doors and drawer fronts are done at the shop and priced as finished doors. Then there is another days labor to put up new trim and hang the doors. If you have never done it before you might figure in an extra day or two for unknowns. A customer usually comes up with something while you are doing the job that wasn't discussed. It usually goes better to say sure I can do that and not add it to their bill than give them a price for every little thing they think of.