Do cabinets need to be sanded first before using this product?

If the surface is clean, dry, and sound, then there is not a need to sand prior to use of the Rust-Oleum Zinsser Bulls Eye 1-2-3 Water-Based Primer and Sealer. Sanding would be required if the surface was not sound. Simply take a 180 or 220 grit sandpaper to help abrade it prior to application and be sure to use an appropriate degreaser prior to priming. - Rust-Oleum Product Support 1