The most common plumbing problems are water and drain line leaks, frozen pipes, hard water deposits and not enough hot water.
A plumber can understand a plumbing system a lot better then the average homeowner, this is important because they can save you time in your day when you have to be working, sheetrock repairs bills and a big mess in your home. Also clogs happen for a reason and sometimes that is the important part, a plumber can usually camera out your line to figure what caused the clog and if it will get clogged again.
If you are on city water, you should have a water meter with a built in flow meter. Turning off your main water supply to the house after the meter will isolate the house to the street. If your flow meter is still running you have a water leak. If the flow meter does not move you do not have a water leak. Also if you turn the water on to the house but are not using any of the fixtures and the flowmeter is spinning you have a water leak.
A water heaters lifetime depends on many things for example, type of water heater, electric vs gas, tankless vs tank style, quality of water and so on. But the average tank style water heater lifetime between gas and electric is between 8-11 years.
This is a question I get a lot, and it depends on how the toilet is working, if you are repairing a toilet and needing a plumber to come work on it, my best advice is the price to pay a plumber to fix it is the same for me to install it. But if you are a do it yourself person, I would say repairing your toilet with a kit from a local store is the cheapest option. I personally think that if you have to plunge a toilet more then once a week it's time for a new toilet, it's not worth anybody's time to try and make a toilet flush better, getting a new bigger better toilet is worth it, trust me!
Yes repairing a Sewer line requires finding the broken pipe and digging around and near it to cut out and install a new piece of pipe. A long sewer line replacement is a different story, horizontal drilling or boring is a new option for running a new sewer line without trenching in your yard!
If your toilet water is running and stops when you move the handle, you have a broken flapper, the flapper needs adjusted by moving that handle And it's only because it has lost its seat on the flush valve hole. Replacing the flapper with a new similar flapping will Usually do the trick. If not check your flapper to handle chain, sometimes it can get hung up on a component inside the tank.
You may have a water leak, or a running fixture for example a toilet will run when the flapper has gone bad, or the fill valve needs adjusted.
Yes, first if your plumbing is in a crawlspace or underneath a trailer house and exposed to the cold, your water lines need a heat tape line taped on your water lines and the. Insulation over the top of the heat top with pipe insulation or regular bath insulation with duct tape wrapped around it tight. Also water lines sometimes can be rerouted in a much better way the first installed and this is important to look out for because heat tape can get expensive especially if you have to hire a plumber and electrician to have it installed.