Spark plug change?
 

My owners manual says change the spark plugs every 4yrs or 60k miles. Why every 4 yrs? Also, it says change the brake fluid every 2 yrs. I have the bleeder and I'm willing to do it but that seems pretty often. Wouldn't every 3 or 4 yrs be ok? Thanks in advance for the advice and help. :)

2 yrs is fine with the quality brake fluids for a street car

Do you track it? IF so, 2 yrs might not be often enough - depends on driving style, heat of track, type of track, etc.

You could send a sample in to a testing lab after 2 years and get the $ water in it if you really want to extend the period. Probably 3 yrs would be ok in a street only car, even one in humid Illinois. Not something I would do...

Are you asking why change the spark plugs every 4 yrs even if low miles?? It might just be to ensure they don't weld themselves to the head... or to avoid any rust buildup in a low miles car.

Note that most here greatly exceed P AG's maint. schedule... you are going in the opposite direction....

I do autocross it a couple times a year...the rest city and hwy miles. The car has 16,500 miles on it now I was wanting to change the brake fluid, but some people said it was not necessary to change it that often unless I'm doing heavy track work on a regular basis. It has been almost 3 yrs now and I think I will change it soon just to be on the safe side because it does have the original fluid. I did not experience any fade at the last autocross in June however. You are correct about the spark plug question. I figured spark plugs just don't go "bad" sitting around in a low mileage car but your explanation makes sense.

I would not exceed the factory specs. for your car. Again you could do a test, but it's so easy why bother.