A microwave is an essential kitchen appliance that is in nearly every U.S. home. The first microwave models were first invented in 1947 by Raytheon engineer Percy LeBaron Spencer. They were made to heat up frozen meals. Like most inventions, they were a far cry from the look and utility that they are today. They also suffered from a lot of skepticism due to the lack of information on radiation at the time. But as time has gone on, it has secured its place in our lives as a huge home improvement.
As we see today, we in the modern world use them for everything from boiling water, heating and reheating snacks, and defrosting frozen food to be piping hot to cooking smaller foods like eggs. Today, microwaves are still more or less the same but has simply become more energy efficient (especially newer type of microwaves). Good electronics should last you a good long time. Since its creation, the longevity of this invention has always been very good, but how long does a microwave last these days?

Difference & Usages
There are several general types of microwaves on the market.
Microwave Drawer: They are installed below a countertop and pulled out like a drawer. Their key difference is the food is placed and removed from the top rather than the front. They are most often used in more modern home kitchens because of their sleek design and, therefore, more costly. Their design can be more accessible if you are shorter or physically impaired, and their design is more usable for left-hand dominant people. Their size varieties are limited because they are made to be built into your cabinetry.
Over the Range (OTR) Microwave: OTR microwaves have been around for a while, although not as long as some. They have been out on the market since their creation by Spencer. They are installed above your range or cooktop in place of a range hood. In addition to their ability to reheat food, they eliminate smoke, steam, and cooking odors with a ventilation system. Because they are made to be mounted over an oven, they also include built-in light meant to lighten the cooking surface (see microwave light replacement guide). Unlike the microwave drawer, they are available in a wider variety of sizes. These are more difficult to replace.

Countertop Microwave: Countertop microwaves are your standard single microwave and were introduced to the American public in 1967 (along with the built-in microwave). With a variety of sizes, they are made to rest on any open surface in your kitchen. These freestanding microwaves are easy to move, and you probably had one you used a lot in college! By far, these types offer the most sizes and power and may allow you to mount them into the wall. They also need the most replacement.
Built-In Microwave: Built-in microwaves can be installed into a wall or cabinet for convenient operation. Built-in microwaves are also a more senior model of the microwave. Like the countertop microwave, they are slightly more costly in price (see microwaves under 200 dollars) and installation and limited in the variety of sizes. A huge positive point is they offer sleek or convenient design - see also retro microwaves - by eliminating the need for countertop space.How Long Does Microwave Oven Last?
Today, the average microwave lasts 7-10 years with normal use. In more busy households with heavy use or a large family, one can expect their microwaves to last about 5 years. But the type of microwave can also play a factor, so make sure to verify what kind of microwave you have as well. The life expectancy of a microwave hasn't really changed since its creation.
OTR and microwave drawer microwaves can generally be expected to last longer than countertop microwaves. If they are running down, it may be a sign that it has been neglected or needs maintenance of some sort. Repair for electronics is also another way to prolong the life of a product. The most important thing about any kitchen appliance is that you treat it thoroughly to help it work for you as long as possible.

What Are Signs That a Microwave is Going Bad?
Besides knowing its general age and lifespan, there are some telltale signs that it might be on its last legs or that there has been poor maintenance on your microwave.
Your microwave is slowing the cooking times. A microwave should be able to make hot water for you in two minutes. If it isn't, this might be a sign the heater in your microwave is malfunctioning. In general, if your microwave takes more time to cook meals than normal, this is a sign that it might be time to retire it.
Worn out buttons: Newer models of microwaves are made to look sleek with a touchpad for a microwave's home screen. With all things, though, the keypad or touchpad can wear down over time. If yours doesn't respond to everything, or you find yourself pushing harder than usual, this might also be a sign that your microwave is aging out.
Loud operating noises: Older microwave models are definitely louder than new ones, but they generally should run at low volume, without sounding excessive. If the microwave is keeping you from having a conversation with someone, or you are actually noticing it in your day to day, this might also be a sign to get someone to look at it.
Maintaining Your Microwave Ovens
Maintenance should be a skill we use with all our home appliances and gadgets. This might not hold true for all things but microwaves are among the most tried and true home appliance technology we know of. Repairs and replacements are natural and can still be made. Use a couple of these simple steps to help maintain your microwave's efficiency, and keep it running smoothly during its life.
Cleaning up after spills. It's just good practice to get into cleaning spills or accidents in your microwave when they occur. Food bits left behind can absorb some of the microwave’s energy (and create burn marks) when you turn it on again, creating a hot spot that damages the interior. On the flip side, take care not to scrub too harshly. The interior of the microwave door has a protective mesh. It is meant to prevent microwaves and radiation from escaping and zapping you, the user. If there is a burning smell, food has probably been left in there for too long and needs cleaning.
(For OTR microwaves or built-in microwaves) Use and clean your fans and filters. There are three types of fans and filters for OTR or range microwaves: the exhaust fan, the grease filter, and the air filter. When cooking, moisture from steam can collect on the underside of the microwave. It is recommended to turn on the exhaust fan on your convection microwave while cooking. While not as efficient as a range hood, it can still help keep the area dry and prolong the lifespan of the kitchen appliance. It doesn't need extensive cleaning; a paper towel or soft cloth will be enough.

In the same vein, the grease filter is also part of the exhaust fan system of an OTR microwave system. The function of grease filters is to trap steam and cooking fumes when cooking. If you let them get too gunky, they can cause your microwave to run less efficiently and can be potentially a fire hazard. Just slide it out to clean. We recommend having rubber gloves on hand and a brief soak for the filter in hot water. Dish detergent can make cleaning it faster as well. It may be possible to clean it in a dishwasher, but we always recommend checking manufacturer instructions first.
The filter system also includes an air filter. It really only needs periodic cleaning or replacing every season, just like your home’s HVAC filter. Cleaning all three is especially important if you often make fried or oily dishes and or have a pet in the house. Heating up or just warming up food is not as taxing on the vent system of the OTR microwave. This can be especially helpful in prolonging the life of your electronic appliance and avoiding less replacement of parts.
Running it on the wrong circuit. Your microwave should not run on the same circuits as bigger appliances like your stovetop oven. As of 2020, NEC code large kitchen appliances must be served by multiple circuits. That's because kitchen appliances are big and take up more energy. If an older property has fewer electrical connections, these may pose a problem too. The conflicting demand for power is too much for one circuit and can threaten your appliances. Often, this issue is resolved at the beginning, when electrical wires are run through the home. Fixing it afterward can be a high cost. If you are renovating and making big updates to your home kitchen with a new microwave, this might be something to consider.

Pushing the weight limit. The capacity of a countertop and OTR microwave is quite limited on dishes. Pay attention when you go to heat heavier meals and big freezer food. The manufacturer’s instructions should include a weight limit on what you can microwave to avoid putting strain on the motor or turntable and damaging the magnets. Learning how to identify the microwave's wattage (a unit of measure for electrical power - see medium wattage) and browsing the manufacturer's guide is a little dry but can save you a lot of headaches in the future.
Conclusion
The average lifespan of your microwave depends on several factors and can apply across the board for any large kitchen appliance or electronic you have at home. That is because it is worth more to you to think of these things like investments, so your microwave lasts.
Even cheaper microwaves just to heat snacks and countertop microwaves can last a good long time if taken care of well. Knowing what is available on the market, the signs on how to maintain one, and the signs of an aging appliance will save you a lot of headaches down the line.