Every household should have a tool box. Here is a list of things that need to go in your tool box:
A pair of common pliers, a pair of slip-joint pliers, a pair of diagonal pliers, a set of screw drivers, a claw hammer, the much needed utility knife, and a pair of wire strippers / crimpers. These items should get you through most common household repairs.
For more complex repairs, call a professional.
Just because you have the tools does not always mean you have the experience to properly use them.