Okay, so I'm finding out that the 2000-2001 Maximas recommend a spark plug change every 100,000 miles, while the 1995-1999 models are every 60,000 miles. They use the exact same spark plug, and are pretty much the same engine. So what's the deal, the 4th gens can go up to 100,000, or the early 5th gens should really be changed at 60,000?

 

Key words are "pretty much the same engine". There are enough differences - just follow the maintenance schedule for your particular year.

 

Different ECU that meters things in a different fashion.

 

I have a 95SE with the original platinum plugs in it. I took the plugs out about six weeks ago for the first time at 58K (mostly highway miles), cleaned them on a wheel and put them back in. My friend's brother did the same with his 99 Maxima with 78K and original plugs.

As far as I'm concerned, unless my fuel economy deteriorates which it hasn't, I'll check mine again at about 70K. The OEM plugs are good for more than 60K and I plan to use them again, rather than copper plugs as I'm a low-mileage user and the car isn't a daily driver.