Plumbers and their heritage 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.
Water where it is not supposed to be - in general
The pipes, whole drainage system, is such an essential thing nowadays, that we rarely even think about it. Until it breaks of course. Than it is the only thing on our minds - mostly because water isn't the best thing for your furniture and flooring.
It is good to have trusted plumber in times like this, but what if he isn't available? There are some times when you need somebody ASAP, and one man business isn't going to come to your aid. Emergency plumbing services is the answer ? company with more than one plumber, on standby.
All in all, it all comes to trust either way ? You need reliable emergency plumbers. But they all usually have what it takes, to fix your water issues. Besides, it's not like you won't try anyway ? right?
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.