The contractor I hired is trying to use staples instead of nails when installing my shingles. Shouldn’t they be using nails?

The National Roofing Contractors Association (NRCA) recommends that galvanized steel nails be used in shingle installation. It’s always a good idea, if uncertain, to check your local building codes and the manufacturer’s recommendations before allowing a contractor to make a unilateral decision about something so intrinsic to the process.