As a cheapskate that would make Tommy proud, I’d like to share my approach to the lightbulb debate.
I always replace both, but I keep the one that did not burn out. When the first one on the new set goes, I put the old one in. When one of those goes, I start the process all over again. It doesn’t really save me any changes, but (a) half the time, I only “get dirty” once, (b) half the time I get the long time between changes, © get all the life out of all of the bulbs.
You are doing more work than necessary. If you just buy two bulbs and keep the second one until you need it, you only change it once instead of twice. Yours might be so easy to change that this isn’t an issue. For my car, changing the bulbs is difficult enough that I don’t want to bother doing twice what I really only need to do once.
What you are doing is just as cheap as my method, but I do less work. Tommy isn’t just cheap. He is also lazy. If you want to make him proud, you are only doing it half way.
And the fourth half is you can put the old bulbs in when you trade in the car and start all over again. This way you’re ahead of the game. Good work!
There are a couple of variables here: 1) was the bulb live out its useful life or did if prematurely fail? 2) How difficult is it to change bulb?
If the bulb lasted as long as one would reasonably expect, it probably makes sense to replace both bulbs if the time involved isn’t too great. On the other hand, I had a 1990 Ford Aerostar and even though these were sealed beam units, they weren’t easy to change. On cars where the hadlights are easy to change, I would do it in pairs–but not the Aerostar. I would only have to get my tools out once.
I attend a small church and serve on its house committee. We have floodlights around the building that are controlled by a photocell. When the bulbs begin to burn out–about every 6 months, I was in the habit of replacing them all since I had to be up on a ladder and each fixture contains 2 bults. One woman on this committee insisted that I was wasting money. She thought I should just change the bulbs as they burned out. Doing it her way, I would be changing bulbs every week. The bulbs all burn the same amount of time and burn out within about 20 hours of each other. My solution has been to change all the bulbs and give the bulbs that have not burned out to this person for use in the floodlights at her house.
I don’t see why you would do something like that. Why not leave the bulb in the headlight until it burns out?
I used to think replace it when it burns out and save the money, But in my latest vehicle after 1 brake and one headlight with in one month had to replace the other, there could be something to it! The downside was it is cheaper to buy a pair than 2 singles. Sure replace them as they burn out but my recent experience leads me to believe they are so finely tuned to life in the big picture you might as well do both.