The underwear analogy

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It seems like a million times the "dirty underwear analogy" has came up whenever discussing using a quality filter for a 2nd interval. Yes I know those who use it think its cute and they feel real clever, but honestly its flat out wrong.

Keeping a filter on after 5,000 miles is not like 'reusing dirty underwear'. Question, on a normal day, how many average people stop in their tracks at 12 noon to rush home to change their underwear out? Why not? Beacuse your underwear at noon is not "dirty, full, or used up" in normal circumstances. If you insist on this analogy, you could change your underwear at 12 noon, but why? In most cases nothing would likely be gained by doing so. Very likely its OK until the end of the day.

This is what goes on with most filters. They are tossed at 5K or so, with another unused 5K capacity wasted. Of course there are exceptions, but those are pretty rare. Look at all the C&P filters posted here. Honda certainly believes in 2X intervals. Notice if Honda says "use a 0-20 or a 0-16 oil" no one dare questions it? But Honda says 2X filter intervals and people scoff.

I get it. For many years I did not want to believe a 2X interval was smart, but I do now. Too many great examples in C&P, and previously owning a Honda, and understanding that significant oil is left in the engine regardless of the filter interval has convinced me. Now going on 10 years of 2X filter intervals and zero issues. All to their own though. Changing a filter every time will not hurt a thing, other than your additional costs. But please, lets leave the "dirty underwear analogy" where it belongs, in the dirty clothes bin. Its just wrong.
 

manicrodder

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It seems like a million times the "dirty underwear analogy" has came up whenever discussing using a quality filter for a 2nd interval. Yes I know those who use it think its cute and they feel real clever, but honestly its flat out wrong.

Keeping a filter on after 5,000 miles is not like 'reusing dirty underwear'. Question, on a normal day, how many average people stop in their tracks at 12 noon to rush home to change their underwear out? Why not? Beacuse your underwear at noon is not "dirty, full, or used up" in normal circumstances. If you insist on this analogy, you could change your underwear at 12 noon, but why? In most cases nothing would likely be gained by doing so. Very likely its OK until the end of the day.

This is what goes on with most filters. They are tossed at 5K or so, with another unused 5K capacity wasted. Of course there are exceptions, but those are pretty rare. Look at all the C&P filters posted here. Honda certainly believes in 2X intervals. Notice if Honda says "use a 0-20 or a 0-16 oil" no one dare questions it? But Honda says 2X filter intervals and people scoff.

I get it. For many years I did not want to believe a 2X interval was smart, but I do now. Too many great examples in C&P, and previously owning a Honda, and understanding that significant oil is left in the engine regardless of the filter interval has convinced me. Now going on 10 years of 2X filter intervals and zero issues. All to their own though. Changing a filter every time will not hurt a thing, other than your additional costs. But please, lets leave the "dirty underwear analogy" where it belongs, in the dirty clothes bin. Its just wrong.
No disrespect but I don't get the comparative values.
 

ZeeOSix

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If you could turn the filter inside out like dirty underwear, it might be ok to use it more than one OCI
That might work for underwear, but not for filters since the dirty side will be on the wrong side where it shouldn't be. 😆
 

ZeeOSix

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Honda certainly believes in 2X intervals. Notice if Honda says "use a 0-20 or a 0-16 oil" no one dare questions it? But Honda says 2X filter intervals and people scoff.
Didn't ya hear ... the Honda oil filter department only hires high school interns to determine oil filtering requirements. 😂 <sarcasm of course>
 
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The underwear analogy made sense back in the day when most cars had filters that held a quart of oil. A lot of filters these days hold a tiny fraction of that.
 
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I bought a Fram Ultra to use on my 2016 CR-V when the current dealer free changes are used up. While the Fram Ultra is a very good filter, and I do plan on using it for 2 OC which will be only about 8 K miles, it is the smallest filter I have ever had for any vehicle I own. The fact that every time I check the oil it looks clean even right before being changed, and that even with 2 OC it will only be about 8 K miles means that even 2 OC is not asking a lot from that filter. At least because it is so small, not much old oil will be in the second OC.
 
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Seeing pics of filters posted here that have gone beyond 10K was a real eye opener (I think Adam has posted some). And of course Dr. Dave here did a 42K run on one.

If I ever revert to a 5K OCI, I'd take my filters to 10K, and change them every other oil change. Right now I'm at a 7K OCI, and determining when to change oil, and when to change oil AND filter, is not as quick for me as changing oil when the thousands column on the odometer hits 5, and changing oil & filter when that column hits 0.
 
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It seems like a million times the "dirty underwear analogy" has came up whenever discussing using a quality filter for a 2nd interval. Yes I know those who use it think its cute and they feel real clever, but honestly its flat out wrong.

Keeping a filter on after 5,000 miles is not like 'reusing dirty underwear'. Question, on a normal day, how many average people stop in their tracks at 12 noon to rush home to change their underwear out? Why not? Beacuse your underwear at noon is not "dirty, full, or used up" in normal circumstances. If you insist on this analogy, you could change your underwear at 12 noon, but why? In most cases nothing would likely be gained by doing so. Very likely its OK until the end of the day.

This is what goes on with most filters. They are tossed at 5K or so, with another unused 5K capacity wasted. Of course there are exceptions, but those are pretty rare. Look at all the C&P filters posted here. Honda certainly believes in 2X intervals. Notice if Honda says "use a 0-20 or a 0-16 oil" no one dare questions it? But Honda says 2X filter intervals and people scoff.

I get it. For many years I did not want to believe a 2X interval was smart, but I do now. Too many great examples in C&P, and previously owning a Honda, and understanding that significant oil is left in the engine regardless of the filter interval has convinced me. Now going on 10 years of 2X filter intervals and zero issues. All to their own though. Changing a filter every time will not hurt a thing, other than your additional costs. But please, lets leave the "dirty underwear analogy" where it belongs, in the dirty clothes bin. Its just wrong.
I kind of look at it as turning your underwear inside out....;)
 
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