Wiper Blades are commonly understood as the whole assembly (the rubber wiper along with the structure that clips into the wiper arm.) The insert is the actual blade portion though, and sometimes these can be replaced separately.
Many aftermarket wiper blades don’t last as long because their rubber is not up to factory grade. While factory grade blades do tend to cost more, this cost may be offset by increased longevity, and offset further if the blade inserts can be replaced instead of the whole wiper blade assemblies.
We want you to have good visibility in the rain, and we don’t want you blinded by the sun shining on smeared glass. Wipers and their performance are also highly visible and audible to the driver and passenger(s) so we want you to be pleased with what you see and enjoy quiet operation.
The quality of factory grade wiper blade rubber is hard to beat. NWB is an OE supplier which also sells to the aftermarket and may be selling comparable rubber in both areas. However, in many cases, aftermarket blades will only last 1-1.5 years before degraded performance results in another replacement and, possibly, a dissatisfied purchaser.
While factory grade wiper blades tend to be more costly, they can pay off in increased longevity. Sometimes it’s also possible to replace just the rubber blade inserts in these wiper blades. While this requires a minor amount of additional labor, it reduces parts cost, and it puts some of the best rubber in those wipers that you can get.
When wipers fail to adequately clear water off the windshield, visibility is limited when driving in the rain.
This occurs when wipers get most of the water off the windshield, but they leave a little bit of visible water behind (which does not immediately evaporate.) When sunlight shines on a smeared glass surface, it can be blinding.
Some folks will be, at least, annoyed by abnormal or undesirable wiper noise, if not bothered by it.
Service via inserts when possible.