You've probably seen some version of the comedy routine in which a full can of paint falls from a ladder onto a hapless homeowner. This is not a scenario you want to repeat in real life!
So, instead of lugging around a full paint can (and courting disaster), try a more moderate approach. Pour a small amount of paint into a clean, empty can or bucket and carry it to your painting spot. This will be easier to handle when you need to climb a ladder, will keep you from wasting paint and, if something does go terribly wrong, the spill won't be as ruinous.
When you're done using the can for the day, cover it with plastic wrap and replace the lid. This will keep it fresh overnight [source: The Family Handyman].