1) An air filter removes more dirt from the air the more clogged it gets. The cleaner the filter, the more dirt that can get through.
2)You will introduce more dirt in the intake system by removing and reinstalling the air filter than you will during the entire life of the air filter if you never touch it.
3) Blowing compressed air (even if you are only blowing the air backwards) puts the dirt in the air and on the wrong side of the filter
4) Blowing air through a filter will degrade the filter and cause it to pass more dirt through it and still look clean.
The only filters that should be blown out are the outer filters on a dual air filter system, commonly found on larger/commercial/industrial/agricultural equipment, and only the outer one. That's what the inner filter is for. When you see dirt in the inner filter, the outer one is compromised and they both should be replaced in a set.
Bro, with all due respect, this is the biggest pile of hogwash I've ever read. At least the first 2 are.
1. Absolutely incorrect. If the air filter traps dirt, it blocks more air. A clean air filter allows more AIR through, not more dirt. To say that a dirty air filter traps more dirt is like saying that a dirty oil filter traps more contaminants. I dare you to find ONE credible source backing this ridiculous claim up. A dirty air filter lets more dirt through, not less. Once it becomes so clogged up it can't trap any more dirt, the dirt has nowhere to go but through the filter into the engine.
2. Absolutely incorrect-IF you take reasonable care. The way the air duct is on my truck, the clean air goes up, so when you change the filter, the dirt falls down. That's fine. I wouldn't blow it out with compressed air, but wiping it with a wet rag would suffice quite nicely.
3. Now this can be true. I've done it when I was poor, not because it's a good idea.
4. This is true or could be true. I wouldn't blow air through it at all, just change it.
I'm a federally licensed mechanic. With all due respect, I wouldn't take much advice from someone who recommends you use a dirty air filter. In fact, changing your air filter regularly can increase fuel mileage and power as the engine isn't starving for air.
As far as cleaning the outer filter, some can be cleaned, some can't. Foam filters are great as they can be cleaned many different ways. The "inner filter" as you call it is sometimes referred to as a "last chance filter" for obvious reasons. Depending on type, it can be cleaned as well. Many motorcycles come with foam filters that are designed to be cleaned and reused. Typically these filters are oiled with a very sticky oil to really make them super effective air filters, yet have a high air throughput. Auto filters, maybe not so much so. Just depends.
But absolutely, under no circumstances, is a dirty air filter better than a clean one.