Most good toilet will recommend replacing a gate valve regardless of its condition. The time to discover if it will work is not during a flood in your bathroom. If you have it replaced with a ball valve then check your water heater and laundry valves, too. Have them replaced at the same time with premium ball valves. Ball valve laundry bibbs make it easy to shut off the water to the washer after each use which may help to prevent floods in the future.
The wax ring is used to seal the drain outlet on the bottom of the toilet to the drain opening in the floor. When a toilet is installed, the ring is placed onto the drain... the toilet is dropped onto the ring... and the toilet bolts (also known as closet bolts) are tightened enough to lock the toilet in place. If that wax gasket ring starts to fail or isn't seated properly? Sewer gasses can sneak out from under your toilet causing your bathroom to have that suspicious smell. It can also cause water line repair to escape, sometimes invisibly, with each flush potentially damaging the floor hidden under the toilet.
The con to time well spent is only if the fix or installation works. Suddenly, when a pipe is squirting water or the dishwasher is leaking all over the floor, that time seems wasted instead of well spent. Now your time is wasted, plus you have to pay for a professional plumber to come over and fix the mess. That time could have been spent doing something else, like golfing or swimming or gardening.
Dirty waste water, after all, leaves your house following the law of gravity. Waste water goes downward to the sewer or septic tank, nice and easy. Behind this simple rule is the multitude of vents and traps to keep the process of waste removal possible. Vents allow air to fill drainpipes, precious air that allow waste water outflow. Traps are those curved S-shaped sections of the pipes under the sink drain. Traps perform a crucial role in forcing most of the water through the drainpipe, but leaving some to seal the area and prevent sewer gas from backing up.
When the drain line stops up it is just a matter of calling an air conditioning contractor to come out and clear the drain line. While he is there he will add an algae preventative to the system to prevent future occurrences. Proper air conditioner maintenance is the key to preventing water line repair leaks.
People who own rental properties are great ones to give you information. With all of the service people needed for maintenance on their units, they typically know who to call and what level of work they perform. Most property owners will be more than happy to give you the information you seek. In fact, they were probably in your shoes at one time.
In short, the emergency plumber you hire should be from a reputable company. If you think that you can rely on him then you should look for another one. An emergency plumber should be skilled and should be able to deliver quality services to everyone.