After painting, turn the can upside down and spray for a few seconds until the paint stops emerging, thus avoiding the paint drying in the valve or cap and it getting clogged. The can is then ready for storage.
Wash and dry the brush by following the instructions on the packaging. Store paint brushes by wrapping the bristles in newspaper and store flat, out of direct sunlight. Alternatively, you can hang the brushes by their handles.
After washing, string roller on rope or dowel to dry. Don't store a roller cover on its side as it will flatten the pile, so stand it upright in a cabinet or box.
Mark the can with color and date or paint the sides so that you know what color is in the can. Ensure the lid has a tight seal. Store in a cool dry area. How long paint lasts in the can depends on how well it was stored. Paint lasts the longest time when the can is full, well sealed and has been stored in a cool dry area (not a damp garden shed). Some paint types will last longer than others.
To check an old can of paint, open it, shake or stir it well and apply it to a test area. Does it smell like paint? Is the consistency of the paint neither too thick nor too thin (like single cream)? Does the test area dry in the time indicated on the can? If the answer is yes to these questions, then the paint is probably fine.
If you are using water based paints, on a hot day, spraying walls with water before you paint will cool them down and make the job faster and easier - you can even paint them when they are damp.