Do the doors in your household squeak every time they are opened or shut? What they want is a drop of multipurpose oil in the hinges, every three months or so, to still their protest.
Wooden doors in baths / toilets tend to decay due to excessive damp and excessive formation of algae Scrub the first sign of decay with soap / detergent and fill the cracks with M-Seal to avoid further damage.
An aluminum or plastic sheet covering lower part of the bath/toilet door upto a height of 12 inches, is very good protection against moisture and decay.
Every year, French polish the doors or use lacquer finish for doors exposed to weather(sun / rain), do not forget top or bottoms of the door, which are normally neglected. While doing this insist on putting a plastic paper below the door so that no marks are left on the floor below the door.
Put dead bolt locks on all exterior doors (including those leading to basements and garages). These could be self-installed.
Make use of the door stoppers, lest the doors bang shut, damaging themselves and cracking the surrounding walls with the force of the impact.
Door fitting and fixtures like latches, handles, aldrops, stoppers etc., are best replaced as soon as they are rendered and unserviceable. Why take chances? All you need is a simple screwdriver to accomplish this job.