I am repainting a high gloss surface (laundry room). Do I need to scuff the surface before painting?

It helps the paint to adhere. You can also wash the wall with TSP or prime it. You don't necessarily need an oil-based primer, Zinsser 1-2-3 is an excellent latex primer. Hope this helps.

First off, wash the surface to make sure soap scum is off the walls. Then, if you are not using a primer, moreso do you sand the surface(especially if the paint is over 72 hrs old).

The new paint has nothing to grab ahold of on a glossy surface cause it is toooo slick. Sanding it puts grooves in it. Paint can hang onto the grooves = staying on the wall.

I think so yes. Don't scratch it up, just lightly sand it with sand paper so the paint has something to hold on to.

If you use a good grade oil base primer and let it dry real good that should do the trick.

wipe it down with liquid deglosser and paint it you can get it at lowes home depot etc.