My dad has Alzheimer’s. At what age should I start routinely checking myself for it?

If your dad has Alzheimer’s, then, yes, your risk is increased—but once you turn 85, you have a 50-50 shot of getting it anyway. So there is no point in “checking yourself” for it. Start making the preventable changes to your life—like getting 20 minutes of exercise every day, eliminating all sugar from your diet, and eating enough prebiotic fiber and healthy fats—now.