Since the OP asked about a toad, you may also want to consider rotating the tires since the front tires do tend to scrub a little more in turns than they would under normal driving situations. Change the out a six years.
On other vehicles, I would consider the use. If you do a lot of highway, high speed travel, I would stick with a six year replacement.
On a vehicle that is just used for low speed in town travel, I would be tempted to go longer with the tires. A lot also depends on location. A tire blow out in the snow is a little more of a problem than a tire blowout down in the Sunbelt states.
