I'm not 100% certain what age is appropriate but I live in area with a high number of seniors and some days I feel like I take my life in my hands navigating the local roads.
Instances include the driver who pulled out in front of us today without looking and was oblivious to our emergency stop behind her. The driver who drove into my car on a roundabout (because she didn't see me), the driver in an automatic car who hit the accelerator instead of the brake narrowly missing me whilst shooting into a car park mouthing "sorry!" as a small child in the back looked terrified. The driver who didn't see my partner and knocked him off his motorbike causing major injuries who turned out to have been sent on two driver awareness courses in the previous year.
My own parents are in their 70s and are good drivers but I wouldn't hesitate to suggest they give up if they started driving around like some of the people I see here who quite frankly terrify me.