When installing a new or replacement lock, be sure the keyway is positioned so that the cuts of the key will be inserted upward. This will reduce the chance of dirt, dust, and water (which can turn to ice in cold weather) settling in the lock mechanism creating a lockout or stiff operation of the cylinder.
When going to buy lumber, eliminate the guesswork by taking along the right gear. Take a good flashlight to be able to see wood in dark lumber sheds, plus a pocket knife to scrape rough-sawn boards to check grain. Also take along a good measuring tape, small square, pencil, notebook, and a pocket calculator if you will need to do much figuring.