Manufactured scheduled maintenance intervals vs. your personal opinion

[boldram]

Gents, Changing spark plugs at 100,000 miles as specified by the manufacturer in the book.
I read a lot of posts where everyone has his own interval set in mind; 30, 40, 60, 80K miles.
I was wondering why very few owners follow the book and on top not even being a professional auto mechanics.
Has not the manufacturer made extensive research and finds 100,000 miles to be a well balanced and optimal time to change spark plugs.
Have anyone noticed a change to the truck performance when changing plugs at 100,000K
Have anyone regraded not changing much earlier?

Thank you
HEMI 5.8

 

[dajogejr]

I can’t believe it’s Friday and the typical poop storm hasn’t ensued.
Changed the plugs on my 15 Hemi at 100K, did it myself, took my time.. no difference before/after.
They were worn, but zero issues. No difference at idle up to redline.
Here’s the range of reasoning you’ll get.

Backyard mechanics of yesteryear. I change my oil ever 3K, Plugs at 25 or 30K.. and I can still tune a Holley 4 barrel by ear…and can eyeball the air gap for points…

Middle of the road.. double that.. to feel more in a safe zone.

Me…. Meh, keep up with maintenance by the book, close as I can. Changing oil when it tells me to is the most important, but don’t feel the need to spend my money on it any more frequently. I can wipe my rear 4 times, but… 2 is sufficient…

Marketing hype sells product and services.
One thing though… just to be clear. Pro Mechanics didn’t write that maintenance schedule. Engineers did… after it got ran by lawyers and accountants…and probably a few more folks prior to print.

I’m not the guy who is a DIYer anymore. I do like doing brakes though…it’s therapy, always did like doing them.
I’ve worked hard and smart to let someone else do it for me…and pay them accordingly.
Can it be done cheaper? Of course. but time is also money, my time and my money…and I spend it how I see fit.