Wikipedia and the definition of plumbing
Quick definition of "plumbing", provided to us by Wikipedia
Plumbing is the system of pipes, drains, fittings, valves, and fixtures installed for the distribution of potable water for drinking, heating and washing, and waterborne waste removal. "Plumbing" also refers to a skilled trade which deals with installation and maintenance.
The plumbing industry is a basic and substantial part of every developed economy. The word derives from the Latin plumbum for lead, as the first effective pipes used in Roman era were lead pipes.
"Plumbing" often denotes the supply and waste system of an individual building, distinguishing it from water supply and sewage systems that serve a group of buildings.
DIY or hiring plumber?
When it comes to repairing things around the house, men often feel compelled to do it themselves, rather than spent money on overpriced expert. More often than not, it is worth the effort, but what happens when you mess with crucial installations, that you know very little about?
Broken chair or squeaky hinges are one thing, but if you mess up with your drainage or plumbing, all hell can break loose. From time to time, it is really wise to call in the plumber - you may pay more than you would want to, but not necessary more than it is worth. Especially if you would do this yourself and mess up.
Besides, do you really have all the necessary things for all the repairs? I doubt that, let alone the tools, which you may or may not have. If you buy unnecessary spare part, what will you do with it? Plumber can always use it, but he probably wouldn't make the mistake in the first place.
To sum up, it is good to do things around your house by yourself, but don't be afraid to call in the specialist from time to time.
Historically about the plumbers by Wikipedia
Quick look in to the history of the plumbers, thanks to Wikipedia:
The word "plumber" dates from the Roman Empire. The Latin for lead is plumbum. Roman roofs used lead in conduits and drain pipes and some were also covered with lead, lead was also used for piping and for making baths. In medieval times anyone who worked with lead was referred to as a plumber as can be seen from an extract of workmen fixing a roof in Westminster Palace and were referred to as plumbers "To Gilbert de Westminster, plumber, working about the roof of the pantry of the little hall, covering it with lead, and about various defects in the roof of the little hall". Thus a person with expertise in working with lead was first known as a Plumbarius which was later shortened to plumber.