A good lawn mower should last from 5 to 10 years and sometimes even 20 years if you take good care of it.
Most times people buy a push lawn mower and use it one or two seasons and then never keep the fuel tank cleaned out or leave fuel in the gas tank.
Then over the winter when they are not mowing the grass the lawn mower sits out and the gasoline turns to varnish which then causes the engine to not start the next season.
So the person throws the push mower out and gets a new one instead of trying to fix the old one.
If you run the lawn mower completely out of gasoline and then add some stabilizer to the fuel tank the lawn mower will usually work just fine the next season.
I have a push lawn mower that I've taken good care of over the years and it's now 20 years old and still running good without a problem.
I bought the push mower new and I have gotten my money's worth out of the lawn mower for many years now and I would gladly buy another one if needed.
I also have a riding lawn mower that I bought new 15 years ago and it's still going strong.
Most people only make a lawn mower either push lawn mower or riding lawn mower last as long as 5 to 10 years and that is okay too.
But if you keep up on the repairs and maintain the lawn mower it can last a few decades.