Do I Need To Sand Cabinets Before Painting Them?

One would hope that the previous finish was applied smooth. You still would need to sand the surface to scuff it so that the new paint has something to adhear to. A gloss finish paint (normal for cabinets) will not allow additional coats to stick as it should, thus causing chips ar flaking.

They also make a liquid sanding product. Instead of all the labor of sandig, you wipe on this chemical and it breaks down the top layer of the paint so that a new coat of paint will adhear to it. This is a much easier way to do it and I found that it is more effective as well.

Yes,sometimes the paint can have an adverse effect with the existing finish which can cause the paint to flake.

As a professional decorator I would recommend lightly sanding, to provide a 'key' and applying a tile or melomine primer (bond coat) before painting.

I washed mine down with TSP, then made sure I had wiped all the tsp off. Then I sanded lighting on both sides. I used two coats of primer because I wanted to get a smooth finish. I also sanded very lightly between coats. I did not take off the entire finish and my cupboards came out great. Just be sure they are free of any grease or dirt and sand them lightly after they are cleaned and in between coats. I also found using oil paint that you cannot go by the drying time on the can! Wait a full twenty four hours before adding the next coat of paint. AND let the paint cure for twenty four to forty eight hours before hanging the cupboards or adding new hardware when you are done. Other wise you risk making dings in the finish.

If the finish has gone uneven then it is better to sand it off and then paint in order to attain a smooth look.

You may only have to sand it smooth.....not enough to remove the old finish but just to smooth out the one that is already on them.

You should definitely at least scuff the cabinets with sandpaper and the wipe them down so they are clean before painting. Otherwise the pint may not stick to the surface and will end up chipping off.