It is really important to know what type of paint you currently have on the walls or trim. Typically, most homes that were built before 1970s had all their trim plus walls and ceilings in kitchen, bath and laundry painted with oil-based paint products. Oil-based paints were most commonly used at that time and by many painters up to the early 2000’s However, if you are still not sure what type of paint yo have, you can perform a quick test.
Regardless of the type of paint, clean all surfaces very well before painting
There are some significant differences between oil and latex based paints. Top quality oil based paints tend to be very smooth when touched. At the same time, cheap acrylic latex paints can have a more rubbery feel. A cheap oil can take forever to dry and yellow in time while a premium grade acrylic will keep its color and be as hard and smooth as an automobile finish (as a matter of fact, many auto finishes are water thinned now!)
They key is to buy the proper paint for the intended surface….exterior trim is often best painted with a softer, more flexible water base acrylic so that the paint flexes and moves with the extreme temperature changes (something oil enamels do not do well) Oil enamel can be the preferred choice for s deep glossy look on a protected front door. There is no one paint type that fits all the needs on all the interior and exterior surfaces of a home.