Needing new tires

All depends on usage. Like I said, driving around town you'd probably never notice it. If you started to run lots of miles, you'd probably notice that the center tread wears out a little before the outers, but on a 70 series you have a lot of sidewall to take up the difference in width. And with that tall of a sidewall it's not like you don't already have a lot of sidewall flex that during harder cornering conditions.
Your right, I don't put a whole lot of miles on my Dart. Just pleasure rides and car shows.