The life expectancy of windshield wipers is between 1 year to 18 months.
It's recommended to replace your windshield wiper blades at least once a year to 18 months.
The more you use the windshield wipers the faster the windshield wipers will wear out and even if the windshield wipers are not used often the rubber on the windshield wiper will degrade and eventually come apart.
Bad windshield wipers can also scratch your windshield when it loses it's rubber part that wipes the windshield.
Inspect your wiper blades every few months and look for any signs that they may need replaced.
Oreilly Auto parts and Autozone will install wiper blades for you at no extra cost when you purchase the windshield wiper blades from them.
I replace my windshield wiper blades every year even though they are still probably good.
It rains a lot here where I am so I don't want the windshield wiper blades to come part during driving and not be able to see the road.