There are other skills plumbers need aside from being able to work with water. One of the most common things that a faucet replace on is fixing water lines.
When you get to the house stand if front of the toilet and locate the water shut off valve. Should be down below the toilet on the wall. Just turn it off (righty-tighty) completely and flush the toilet. All the water should have left the tank, well at least most of it. If there is remaining water line repair get it out with paper towels or a rag. The important thing is that no more water came in. If it did then your valve is not shut all the way or not working and you need additional help.
After you have the stems out you should be able to find the washer on the "inside" end. If it is nicked, torn or brittle it is likely the cause of your drip. Even if it looks brand new, go ahead and replace it. You've already come this far. You can get replacement washers at almost any hardware store. Sometimes you may want to replace the whole stem, especially if the handle end is stripped out. It's best to just take the stem with you to the store and see if you can match it up. Most Do It Yourself stores have replacement stems for many popular brands. If your valve has a center diverter valve to switch the waterfrom the tub spout to the shower head the same process applies. Many times it is easier to replace the diverter stem than to repair it. This really depends on the design of the stem.
Working on the gas lines is also a complex job that only a licensed plumber can handle because it is very dangerous. Small leaks can't always be detected by odor alone, but a licensed professional has the proper equipment that's needed to ensure that you don't have any leaks in the line.
If the area around the fan isn't clean and dry, or if dust or any sort of growth has accumulated on the blades or inside the exhaust duct, it may be a warning sign of excess moisture build-up. Clean the water line repair fan and area well. Then double- check that the fan is operating properly.
If you do in fact choose to replace it, there is a good chance that you have an Aqua Magic IV which is no longer produced and has been replaced with the new Aqua Magic V. If you are replacing your toilet and have the Thetford Aqua Magic IV, there are other options such as the Thetford Aqua Magic Style Plus or Thetford Bravura Toilet as well as choices from the Sealand line of toilets. You will have to choose whether you want a hand or foot flush, and whether you want to stay with plastic or upgrade to china. You will also have the choice of adding a water saver. Regardless of which choice you make you will most likely be happy with the quality and dependability of any product available.
Windshield repair techs come and go on a daily basis. The majority struggle to survive. Most fail. It's not that they're not good at what they do, it's not that they don't have the skills, it's not that they're not willing to work hard, it's their lack of MARKETING Training. That's the bottom line: It all comes down to proper marketing strategies.