Hardened Valve Seats or Not?

I have come across many articles over the years, that insisted that the 71-up heads had the hardened seats. I cant speak to the truth about it.
It "seems to me" that if you had 71 heads,and with youre limited useage, it would be a non-issue for many years to come.
With pre 71 heads? Hmmmmm. I think I would patiently look for and freshen up a set of later heads, or magnums, and put them on the shelf, at the ready. See how many years the current heads go, and then report back.
Kansas winters arent so short that you cant find the time to swap heads at a later date; say 2025?
And maybe in a year or two the bug bites, and youll be contemplating some performance heads, and kicking yourself for the money you spent on the hardened seats, today.
JMO