There are other skills plumbers need aside from being able to work with water. One of the most common things that a trustworthy plumber on is fixing water lines.
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.
You don't want to be paying your plumber to clear the area before they start work particularly if you are paying an hourly rate. Empty cupboards and make sure there is nothing that may cost the plumber time and you money gaining access to the job.
A plumber becomes a journeyman once they complete their apprenticeship program and they can apply to be licensed. Most of the plumbers today are in the field of journeyman. To get a license to be a journeyman, you need to pass an exam and pay a licensing fee.
Be certain that the bathroom exhaust fan vents to the outdoors, not into the house or attic. If the exterior vent dampers don't operate properly or water line repair don't seat well have them fixed or replaced.
From your own point of view, it is important that the plumber be trustworthy and credible. Ensure the plumber comes with at least two strong references which you can verify. This will help you be more secure and suffer less anxiety.
Be sure to choose a licensed glass shop in your area. There are a lot fly by night shops out there. You pay a lot of money for your vehicles so you want quality work at a fair price. Do the homework before you have this procedure done because proper preparation before installing a windshield will keep your car from having rust issues which may cause water leaks.