Each state has differing laws regarding drivers license renewal periods. The spectrum is large, where some states test drivers quite frequently as they age, while others may only need a single renewal in their entire lifetime, or none at all! The state of Arizona stands on the far side of that spectrum, whereupon inspecting my license issued in 2010, wouldn’t have to visit the Motor Vehicle Department for a new license until 2052, a full 42 years later!
With this point being commonly debated, the Royal Society for the Prevention of Accidents (RoSPA) published research suggesting that no distinct age (including age 70) appears to arbitrarily exist where vision, responsiveness, etc. distinctly drops amongst the general population. Degradation of physical health seems to occur at a slow and steady rate, beginning for different individuals at different times.
Keeping that research in mind, many believe that a higher frequency of renewals is a more gauged, accurate approach. To the contrary, others suggest that regardless of individual health or number of renewals by age 70, it seems logical that statistically speaking, the likelihood of at least some significant reduction in health has occurred in most drivers, warranting a renewal no matter what.
RoSPA declines taking an official stance in either direction, but encourages aging drivers to undergo consistent formal medical examinations, both at age 70 and well before. By having legitimate physiological results in hand, drivers can make more informed decisions as to if, when, and how they drive. Such advice seems to be prudent for us all.