Wiper Blade maintenance

Your current blades leave streaks or miss sections of your windshield
Your current blades leave a haze on the windshield
You haven’t replaced them in the past 12 months or don’t recall ever replacing them

Inspect windshield wipers every six months for wear and damage, and change at least once a year.
Do not wait to replace worn and damaged wipers until the bad weather hits or visibility is so deteriorated that safety is compromised. Eyestrain from poor visibility can lead to driver fatigue and anxiety. A regular inspection schedule will help avoid potentially dangerous situations.
Give your wiper blade rubber elements a quick cleaning when filling up with gas. After the windshield has been cleaned using service center's washer solvent and squeegee, wipe down the rubber with a paper towel. Doing so removes any loose dirt and most road grime that can lead to streaking, smearing or hazing.
Use an ice scraper as much as possible when de-icing vehicles. Allow plenty of time to warm up the vehicle with the defroster on "high" to loosen as much ice and snow as possible. Do not use windshield wipers as ice scrapers.

Sun: ultraviolet light and ozone deterioration
Oil: car waxes and exhaust hold rubber-deteriorating oil
Airborne debris: sand, mud and dust carried in the wind
Moisture: Acid rain and salt water (in moist air both near the shore and inland)
Temperature: extreme cold and heat cause hardening and softening of the rubber element

Streaking: blurry vision caused by dry or dirty rubber blades
Chattering: skipping of the blade caused by a permanent set or curve in the rubber of old blades
Lift-off: over time the arm tension deteriorates causing the blades to lift
Squealing: worn blade edges cause excessive friction and ultimately noise
Windshield scoring: in extreme cases, the wiper has deteriorated enough to cause windshield "scoring"

Flex rubber squeegee back and forth to see if it is still flexible. Aged squeegees will have difficulty conforming to the shape of your windshield and create streaks
Check squeegee wiping edge for rounded edges which can prevent the wiper blade from making strong contact with the windshield and reduces wipe equality
Tug to ensure wiper blade has been securely installed on the wiper arm
Check that squeegee is secure in the wiper frame

Wiper blades that are worn can cause excessive load on the wiper motor and linkage and lead to premature failure
If the blade is worn to the point where the metal frame can come into contact with the windshield at any point of rotation, then scratching/grooving can occur. In some cases windshield replacement would be the only fix.
If the blades do not clean well, the tendency is to use your washer fluid repeatedly until the windshield is clean. This generally causes excessive washer system and washer fluid use and could end up costing you as much as replacement blades or even more
Driver and passenger wiper blades are different sizes