Dependent (more or less) on the substrate you're painting: natural hardwood/softwood timbers, artificial bonded boards, veneer-faced ply etc. & the product; acrylic, oil or 2-pack lacquer, enamel, emulsion or milk paint etc. Each variable can provide different results.
Generally the first coat (again dependent on the nature & type of finish used) will raise the "grain" considerably, & require a slightly coarser sand to remove these raised fibre ends back to a smoother substrate face. Especially if thinned as is often recommended by finish manufacturers.
Subsequent coats will require less intensive &/or higher grit count intermediate sanding, just to denib the previous surface & provide an adequate key for the new coat. I often use a quartered sheet of 240G for the first & 400G for subsequent coats. I like to use the quarter folded paper sheets in my hand only, as this (possibly erroneously) allows a more intimate "feel" of the surface being denibbed.
I seem to get the best results when each surface is thoroughly not only dry but sufficiently hardened too, which is often temperature dependent & may take more than 24hrs between coats.