Painting Garage Walls
if it has been longer than 30 days since the primer was applied you should prime again. i like Sherwin-Williams PrepRite ProBlock latex.
after the walls are primed, i like to use an exterior satin in garages. its more durable than an interior paint. try Sherwin-Williams A-100 satin latex.
as far as your brush and roller - wash your brush out every night, and if you use a roller pan try putting it in a trash bag with the roller and make it air tight. it will last for a day or two. or dump the paint back in the gallon and roll the roller up in plastic, tucking the ends into the roller sleeve. when you are done throw the roller cover away, don't be cheap they are only $5