If your microwave has hit the bucket, then it's time to start the process of buying a new one. If you've called a repairman and the microwave dielectric materials are shot, then it's time to pony up some cash and buy a new one. Here is a quick guide on some things to consider when buying a new microwave.
Type
The type of microwave you need will really depend on the layout of your kitchen. If you have space above a stove, an over-the-range microwave may be the way to go in order to conserve space. If you don't have the ability to add an over-the-range microwave, then a countertop microwave is the best alternative as they are the most affordable.
The way the microwave cooks the food can also differ between standard and convection microwaves. Convection microwaves utilize a different method for cooking food as it uses a fan to circulate hot air instead of electromagnetic waves.
If you care about having options when it comes to how your microwave cooks your food, a convection microwave is probably the right choice for you as roasting, baking, and broiling are all able to be accomplished with this type of microwave.
Size
Microwaves come in many different sizes, so it's important to consider the size you will need. The best way to do this is to see the footprint the microwave will take on your countertop. Next, you'll want to consider the types of food you will want to cook in the microwave. If the microwave will be used to just reheat leftovers, then you can probably get by with a smaller microwave. However, if you want to be able to convention cook a whole chicken, you will want to make sure you get a microwave that will be the appropriate size to handle that.
Wattage
The main thing to know here is that the higher the wattage value, the faster your food will cook. The downside to high wattage is that you increase your risk of tripping a breaker, or not having enough amperage available on your electric line to handle long cook times. A good rule of thumb is to find a microwave that is at least 1000 watts as that should be the baseline to cooking food well.
As you can see, there are many things to consider when selecting a microwave, so take this advice and find the best microwave that fits your budget and kitchen.