When to get my OEM tires changed?

For 70k you're doing really good to wear your OEM tires.
But yes, it definitely is time for new sets.

 

I don't understand the dealer's comments, but it's definitely time for new tires. I'd say you're about 69,999 miles overdue for good ones.

 

the tires wear faster because they are a softer compound. The fact that you have 70k on those tires is hard to believe. Mine have 35,000 and they are junk. Do yourself a favor and get better tires than the integrities

 

New tires are in order, but a dealer will probably charge you more than a tire shop. After reviewing _Tire Rack_ test data (taken on a Prius!) and living in a climate without snow I intend to replace mine with Goodyear Assurance FuelMax.

 

When to replace the OEM tires? The minute you drive the car off the showroom floor. I wouldn't drive anywhere with the stock tires. Also, don't buy tires from the dealer - there are too many tire shops competing for your money with better deals.

 

I am at 54500 miles and almost at the point where I can see the top of Lincoln's head on a penny (so will need to change them soon). I figure breaking would wear them out faster than not breaking. You drag more rubber on the pavement when breaking, right?

 

You should measure the tread depth yourself and see if it needs it. Good for you that you got 70k on the original tires.
Oh, the dealer is smoking something funny Ask for some tech manual data for his claim