For mysterious, quantum-mechanical reasons, the screws that hold handles and doorknobs always eventually work loose. A few drops of thread-locking compound will permanently fix the problem, yet still allow you to remove the screw with ordinary tools if you need to later. A heavier-duty variety is also available for large bolts and machinery.
How to Repair a Squeaky Floor - Fill with caulk, Smooth the bead, Push the bead of polyurethane construction adhesive deeper into the flooring gap with a plastic spoon instead of your finger. This adhesive is extremely sticky. Wear gloves when handling it and expect that any tools you use to work the adhesive will have to be cleaned with paint thinner, or in the case of the spoon, just throw away.
How to Upgrade your Builder Grade Mirror - Frame it! Cost us around $30