Good question Nick. I manage several rental units and have dealt with the same situations. Originally, flat paints were used in most of the rentals and almost every couple of years they needed repainting especially if kids were in the unit. Flat paint is hard to wash and very susceptible to marring and finger prints etc. The newer flat enamels are better, but not great. I changed over to a harder eggshell finish. Depending on the time a tenant is there, the eggshell really outlasted flat, usually good for 3 to 5 years unless damaged. Satin enamel works great for ceilings, hides marginal imperfections and very easy to clean between tenants. I have also found that since looks is more important than durability, I have used a lot of PVA grade wall paints from Ben Mor. At contractor price, it can be almost half as expensive than premium grade paints, covers well, lasts for several years. I have given up on expecting paints to be show ready after a few years in a rental. Cleaning and touching up walls takes almost as long as painting so a new quick same color wall paint job between tenants freshens up the place and smells new when showing the apartment. I tend to use just a couple of colors for most everything, so I buy 5 gal cans for economy, batch small leftovers and treat older paints with Flotrol. Be sure to keep the color formula in a notebook (ask for an extra sticker) so you can buy a good match later. Changing colors always requires two coats, but one coat of same color is normally fine. You can use your leftovers with new paint if you strain it through a mesh colander and batch it with your new paint, thus slight color changes disappear.
There are two critical steps in prepping kitchen walls.
Clean and degloss
Cleaning is critical: TSP or TSP substitute.
Deglossing: either light sanding (120 grit) or a chemical deglosser
Once a surface is deglossed, it should be primed, especially if going from one paint type to another.
A deglossed oil undercoat can be primed with a latex primer. Either oil or latex can then be used as a topcoat.
A deglossed oil undercoat can be primed with a oil primer. Either oil or latex can then be used as a topcoat.
It is better to stick within families of paint types, if you can, but going back and forth between types is possible with primers.
At this stage in coating, I'd let everything dry for a week, then sand lightly. If the previous layers are adhering, then proceed with latex primer, latex topcoat.
If,, however, they are sloughing or chipping or you can easily pull a layer off if you leave painters tape on overnight (and then pull it off), then you must sand down to the last well adhered layer and then repaint. Good luck.
Best Answer
The drywall probably isn't reversed. Old drywall paper darkens with UV exposure, and many from the 80s and earlier look just like that. It's not intended to be a finished surface.
You can be sure by looking at the tapered edge joints--if there's a paper edge showing you're seeing the back side. If it's smooth paper wrapped all the way around it's the front.
The right approach was to seal the surface first with PVA primer/sealer or equivalent. It would've then probably taken one coat of quality paint, or two at most, to arrive at a satisfactory finish for a garage.
At this point I'd prime with a good blocking sealer and repaint with just one coat, applied carefully and properly. Rather, I'd expect the "professional" to do that.