Some version of toilet has been used in human civilization for thousands of years. However, the modern flush toilet is an innovation that has been around for less than 150 years. The modern toilet is one of the greatest sanitary inventions that the world has known as it has stopped the spread of many common diseases in the first world.
Most people today take the toilet for granted; at least until it breaks down. Modern flush toilets contain many parts that must work together in order to operate properly. If you have noticed that your toilet is continually making noise, is leaking from the base, or if the fill level is too low or too high, you should think about having your toilet looked at by a professional.
If you are looking into new toilets, you may also wish to consider some new technologies that can save you money on your water bill by using water more efficiently.