Making sure your microwave is safe is not hard to do, but most people never question that it might not be. If your microwave starts leaking, it can be very bad for your health and others who are around it. There are inexpensive testers that will let you know whether your microwave is safe.
I am giving you a link to one that costs just under $40.00 American. It checks to see whether all four zones are working okay and you can also check outside to see if the seals are leaking. Here is the link: http://www.toolexperts.com/micro-check-microwave-leak-detector-tester.html
Here is another microwave tester that is only about ten dollars: http://www.geostar.com/mrmicrowave/magic.htm
You can place the dish to be tested inside the microwave and turn the microwave on for a few seconds. If you see any arcs or sparks inside the microwave, turn off the microwave immediately. The dish has also failed if it starts smoking or anything else that looks bad.
My preference for this test is to plug the microwave into a power strip with an on/off switch. I turn off the microwave from a safe distance if the dish inside fails the test. I use a broom handle to turn it off.
The above test is probably not a good idea, but I sure am not paying an expert to test every potential microwave dish in my home.
Some glass dishes have a small amount of metal in them and should not be used in a microwave. I have even run across some that were labelled as microwaveable. Ergo, another test. You put some water in the glass dish and heat it in the microwave for one minute. Take the dish out and see whether the water is hot, but the dish is cool. If so, the dish passed the test. If the dish is hot and the water is hot, the dish flunked. Do not use that dish in the microwave.
If you have mugs or other dishes decorated with metallic designs, it is pretty sure they will not be microwave safe. You can save yourself the trouble of testing them and just not use them in the microwave.
I took a class in how to use a microwave a long time ago. It emphasized "standing time". This is about the time after the microwave oven stops operating, but the microwaves are still bouncing around inside the food you just cooked. Those bouncing microwaves in your food are still cooking the food even with the oven turned off. You are supposed to let the food, "rest", do "carryover cooking time", or do "standing time".
If you eat the food while it should be sitting while it finishes cooking, that extra cooking can be going on inside you. You could be cooking your insides. I don't like this idea, so I like to pay attention to the "standing time" rule of thumb estimate for how long to let the food sit and cook by itself before I eat it.
I was told by a professional home economist, with a college degree in home economics science, that it is safer to allow about as long as the microwave cooking time plus half again, for standing time.
There are a couple of other things to watch out for in microwave cooking. One is uneven cooking. If a recipe tells you to stir at certain intervals, do it. If you do not follow the directions it can ruin your food or even make you sick.
The other problem is with cooking times and the food not reaching a high enough temperature to kill bacteria. This can be caused because your recipe was made for a different power of microwave than yours. The way to solve this problem is a bit too long for this blog post, so I am giving you a link to a site which tells you how to solve your microwave problem. The site is on, "About.com", and it is for a cooking "guide" on the site. She is excellent at her job: http://video.about.com/busycooks/Cooking-With-a-Microwave-Tips.htm
It is a bad idea to attempt do-it-yourself microwave repair. Let an expert do it. They earn their pay with the risks they take.
Microwave ovens actually save energy when you cook things in them that do not take a long time to cook. The longer you cook something in a microwave, the less energy efficient they are. Your Thanksgiving Turkey is probably better done in the regular oven if you are interested in saving energy.
I was reluctant to begin using a microwave oven a long time ago when I was gifted with my first one. I took the class to learn how to use it right and be safe with it. I used it for many years.
Friends have convinced me that microwaves may be as unhealthy for cooking your food as I originally suspected. I have again stopped using a microwave oven. I barely miss it since I have come up with substitutes for it.
I also have another reason for not wanting to use a microwave all the time. Electric power in a TEOTAWKI scenario could be rare. If I use a microwave all the time, it will make cooking in the aforementioned scenario, more difficult. I think things could be quite difficult enough without adding problems knowing how to cook the food that is available.
One of these is bamboo steamer baskets. They are more efficient when you want to heat up several dishes at the same time in a stack of dishes over the same heat source. They do not take long to cook or re-heat food on them.
I also use a griddle on a burner on the stove top for things like tortillas, thin slices of bread and melting cheese on something.
I don't know whether I will continue with my self-imposed ban on microwaves, or if so, for how long. For now, it makes me happy.