Why is it better to replace bulbs in pairs?
When one of my friends who plays the guitar breaks a string, he would often change the entire strings. I found that odd. All he really needed to change was the one string that broke. When I asked him about his reason, he said, “ Typically, when a string breaks, that tells me that other strings are not that far from breaking, “ And added, “ Also, all strings have a certain lifespan. As it ages, the sound also degrades over time.” That made sense to me, and it dawned on me. One of many questions we get here at HID Concept is, “My headlight bulb burnt out, and I just need “one” bulb replaced.” Most mechanics I know always recommend to change tires, brakes, shocks and windshield wipers in pairs. This notion applies the same to the automotive light bulbs.
Automotive light bulbs, from HIDs to D2s, dim over time. This is an important fact that some of the motorists overlook when they replaced the burnt out bulbs. See the video provided by Philips Auto Lighting about the importance of changing the bulbs in pairs. It may shine some light on the importance of replacing the bulbs in pairs.
As the Philips video demonstrates, you absolutely can see the disadvantage of having two different sets of headlights. Just like my friend’s guitar and string changing, replacing both bulbs, (even though the existing bulb looks okay) is a uniform way to maintain your vehicle. By doing so, you are also saving time by not replacing the other bulb when it eventually goes out. Another aspect is the aesthetic of vehicle. Taking HID bulbs, for example, most drivers love HID bulb for its brightness and the color. However, HID bulbs too will degrade as the time passes, and the color usually becomes irregular to get whiter and bluer than how it was originally. Along with it, the luminosity of the bulb will be considerably dimmer than a new bulb. Simply put, in order to have a color matching HID headlights, the recommendation again is to replace the bulbs in pairs.
However, the most important reason for changing the car headlight bulbs in pairs is for the safety- Both for you and the other drivers around you. A few years ago, I was driving on a rural highway where the street lights were not available. I turned my head to the right to look before making the lane change, and I saw a dark Dodge driving right next to me! I don’t mean black Dodge, but a driver who forgot to turn on the headlight, dark. It was like, swimming in an ocean at night and a gigantic shark crept right next to me. Not having a proper headlight can cause a similar situation. As I mentioned above, headlight bulbs emit less light as they age. Properly replacing headlight bulbs is as fundamental as all other important maintenance. Having one dimmed light and/or completely burn out during driving can cause a difficult situation for you and the other drivers.
I am going to sound like an “Auto light bulb” salesman making an “Auto light bulb” sales pitch, but this is one of the reasons why Philips, Osram, and even our own brand, “DAMA” is sold in pairs. Of course, you can always purchase in single units, but we understand the importance and convivence of replacing the bulbs in pairs.