Osram offers both motorists and garages some very useful and practical advice on its website and one of the major recommendations is that bulbs, especially headlight bulbs, should always be replaced in pairs. 

Forward thinking garages, who place customer satisfaction high on their priority list, will generally adopt best practice and across a range of vehicle components, such as wiper blades, shocks and brake pads offering replacement in pairs. This is especially important when it comes to automotive bulbs. 

Replacing just one failed bulb can result in an unbalanced or unpredictable headlight beam that can cause serious hazards for both the driver of that vehicle and other drivers and road users. Vehicles are designed so that they are working to their best and their safest when both headlights are functioning equally. Only then will the driver get the full advantage of the combined headlight beam increasing visibility and helping to spot dangers sooner. An imbalance also means that the vehicle is harder to see and may even be mistaken for a motorcycle. 

As well as the safety issue, there is also the question of cost and convenience. Bulbs will be subject to the same stresses and strains over time. They will deteriorate at the same rate, which usually means that if one bulb fails, then the other will not be far behind. 

If a garage only replaces a single bulb, without even offering the option to change the second, then this can lead to unhappy customers. The chances are a customer will have to comeback within a short period to have the second bulb changed. This means the inconvenience of two trips and the potential for two fitting charges, which can be significant with some of the newer headlight configurations. Customers will not be happy with this and it could have an impact on future business. However, the situation can be easily avoided by changing bulbs in pairs. 

For more information on bulb change best practice please click here.