if polishing/finishing by hand you could air on the side of caution the following day. depends on tempreture ect. if using a mop, give it a few days and use plenty of water. the paint will be soft under the surface and will melt/smudge oh so easy. im not a painter btw but did a fair bit with a mate who is a sprayer. its all about knowing when to stop. in a nut shell the longer it cures the better. more elbow grease is still better than ruining your nice new paint.