For clear visibility, driving safety and wiping performance, wiper blades should be replaced at the first sign of trouble. The best recommendation for your customers is to have their wiper blades inspected every six months and changed at least once each year. And, if they drive many wintertime miles, suggest that they invest in a set of winter wiper blades that can be like snow tires for the windshield.

Even with clues like streaking, chattering and noisy ­operation that signal that the wipers have reached the end of the road, many people wait until they can barely see where they’re going before they consider buying a new set of blades. People get too used to poor visibility, but that can get dangerous quickly, especially when the weather takes a turn for the worse and the wipers are needed to clear the glass.

Specialty winter wiper blades are designed to take on snow, ice and sub-zero temperatures. A heavy-gauge wiper element can ­resist tearing in cold weather and eliminate chatter for a smoother, quieter wipe.

The main challenge for a ­winter wiper blade is snow and ice. On regular frame-style wiper blades, snow and ice can clog the frame and prevent the wiper from making even contact.

Winter blades may use a rubber boot over the frame to prevent snow/ice buildup, and newer frameless-style wiper blades do not ­experience this problem.

Both blades should be ­replaced at the same time because chances are both blades are the same age and condition. And don’t forget the rear wiper blades on minivans, SUVs and hatchbacks. Back wiper blades are often more neglected than the ones up front because they’re used less often, but they’re no less important than the front blades.

It’s also important to check the operation of the windshield washers. If one side of the washer doesn’t work, a delivery hose could be broken or a ­nozzle could be clogged. If the washer system completely fails to work, the problem could be a dry reservoir, bad washer pump, a blown fuse or a bad washer switch.

In many cases, the reservoir is damaged by freezing water or washer fluid, so the technician should always check for leaks after refilling. While less expensive washer fluids work well in summer, they can actually ice the windshield over during wintertime driving. For safety’s sake, techs should always recommend washer fluids ­designed for sub-freezing winter temperatures.