Cabinets weather finishing them with newer water base or with varnishes that have hardeners mixed into it (conversion varnishes) the steps you take to doing quality work is vital to a clean and professional look. First why go with water base paints and primers? Water base is easy to work with takes less skill and inherently cost less money only the steps for painting is still similar. For Spraying conversion varnish the material is typically 20% to 40% more expensive, has bigger time constraints, takes more time and cleaners to clean the required tools and takes a more experienced tradesman to apply the varnish properly all making it a more costly option yet the benefit is that it is stronger and flexes with the wood making for a finish that looks newer longer.
When it comes to preparing cabinets if they are old and they are being refinished the fist step is to remove the doors, clean doors and frames with TSP, Sand, Prime if needed, Paint with a High Pressure Low Volume (HPLV) sprayer for a fine finish. When it comes to spraying the doors there are two options having the doors painted while hanging or left flat so you can only paint one side at a time. If the doors are done one side at a time while flat the finish self levels leaving a more desired finish yet takes more time. Once the doors have cured (read the cure time on the material that is being used) you can install the doors.