Putty(spackle) and Caulk
Weather you are repainting or have a new construction project, you must do your putty and caulking to ensure a professional look.
Spackle dries quickly and sands easy with very minimal shrinkage. When spackle on walls are required it is because small dings and scratches have occurred. Some baseboards and trim need putty when a nail hole is visible. When patching a nick on your walls, start with sanding the spot. You only need to sand just enough to knock off any rough areas or to clean up the surface. Take a putty knife that is larger than the patch and apply an amount of spackle slightly larger than the damaged area. The goal here is to leave enough spackle behind to fill the damaged area but not too much on the surrounding area as to leave a bump. Let dry and use a 220 grit and sand to flatten the patch as much as possible.
Caulking will bridge the gaps between walls and baseboard and trim with a flexible tough surface. First thing first make sure you use a paintable caulking , to many times we grab any caulk product and not knowing it was a silicone find that paint will not stick to it. Caulk tubes have marks on the tip for cutting different sizes to dispense the caulk. When you are caulk finishing baseboards and door trim use the smallest cut mark. If it is cut too large to much product will come out leaving a mess. You will have more control with the smaller cut on your caulk tube nozzle.
Ask your local paint store for demonstrations of the spackle and caulk products. Seeing is believing in some things.