repainting kitchen cabinets

A hardware store guy who never steered me wrong said that if paint is intact and in good condition, there was no reason to prime it. Just make sure it's clean, and that you don't leave any residue from whatever you clean it with. As far as the method, I think I'd lean toward spraying the cabinet doors, since they're so easy to remove and set up over an ocean of newspapers surrounded by cardboard walls.

No need to prime, just degloss existing paint either by sanding or chemically (TSP) and be sure the surface is clean.

Did you paint in oil or latex, the reason is oil and grease gets imbedded in paint and can and does make failure of cabinets. Kitchens are in the harshest invironments if you cook, the residues litteraly embed themselves in paint making real degreasing and cleaning sometimes impossible with latex since the chemicals needed will eat the latex up. So I have no idea of how they have been maintained by you, use a white rag , if you clean any residue off you have a major clean job to do, around the handles if where hand oils will realy hurt and be sometimes impossible to remove. 2 years is not much, but often 10yr plus finishes must be stripped only because hand oils have made new finish bonding impossible. So its realy up to their condition , your cooking and their cleaning.

Are you manually typing arrows to the left of your responses?

TSP, not TSF. Trisodium phosphate. Neither hard to use nor messy. It is a powder to mix with water, available at paint stores et al. Follow the directions, wear rubber gloves.

I'm assuming your topcoat paint was oil too and either glossy or semi-gloss.