I'm assuming you are referring to a garage floor coating. If so, I recommend a single-part polyurea garage floor coating kit. Single-part polyurea does not require the mixing of A and B components. Pour just enough out of the container to coat what is necessary and seal it back up. DO NOT pour excess from the paint tray back into the container. It will stay fresh in the sealed container long enough for a section to completely cure before you use it again. I posted an article below that discusses single-part polyurea and where you can find it.
Once you mix a 2-part coating such as epoxy, the chemical reaction has started. After that, you use it or lose it. It's harder to find a 2-part kit with the correct square footage you need for each section. The other option with 2-part products is to measure out only what you need of part-A and part-B for a particular square footage before you mix the components.
Discover the secret of polyurea garage floor coating kits. See why they are easiest to apply, have the best protection and last 4x as long as standard epoxy.
allgaragefloors.com