Long ago, in a dark (pun intended) part of American history, it used to be
change filter every "other" oil change.  I don't practice this but I know
people that still do and won't change thier ways.  The book also states
these same facts.  4 qts. without filter and 5 qts. with.  Read into that
what you want.  There are people out there that believe changing oil is a
ploy by the oil companies to get you to buy more oil.  When my brother told
me that I asked him how much stock in the Brooklyn Bridge he also owned.

There are a few out there! I tossed the old filter on some guy's 68
Impala (looked like it was a week old) without even thinking to ask him
if he wanted the filter changed. He sees me screwing on the new one, and
comes running into the bay, yelling, "I didn't want the filter changed!"
I went, "huh?" He's all excited, so I finally just said, "I won't charge
you for it!" He then proceeds to pull the manual out, and it says to
change the filter every other oil change, and by golly, that's what he
wants, regardless of how stupid it is! We tried to explain why it was a
bad idea, but he insisted.

I ended up fishing the old filter out of the catch bucket and putting it
back on.

That guy is now a judge. Scary.

BDK