No mystery to it. Here is exactly what happens from the moment you call to the moment we hand the job back.
A door comes off and gets examined at the edge to identify wood, MDF, thermofoil, or laminate. That single check determines the primer, the risk, and a large share of the price.
Plastic sheeting seals the kitchen from the rest of the house, countertops and floors are covered, and doors and hardware come off and get labeled before any sanding starts.
Degreasing comes first because sanding a greasy surface grinds oil into the wood. Then scuff-sanding, filling of dents and old hardware holes, and grain filling if the finish calls for it.
A bonding primer is applied and sanded smooth, then two thin topcoats go on with light sanding between. Doors dry flat on racks so the coating levels instead of running at the edges.
Doors return to their labeled openings, hinges get adjusted for even reveals, and bumpers go on. The finish is usable in days but keeps hardening for two to four weeks.
None of this is required — it just makes the visit quicker.