We don't think about our kidneys much. If we are lucky, we get appropriate medical care and our doctor keeps an eye on them with a lab test called a Comprehensive Metabolic Profile (CMP).
If we don't have the money or inclination to see doctors, our kidneys can lose most of their function without causing symptoms. This is especially likely for people with diabetes.
We are fine on Monday, feel somewhat ill through the week, go to urgent care and learn that our kidneys aren't working. We need dialysis.
Dialysis centers have a term—"crash-start"—for people in that category. There's no time to adjust the diet or to place a planned, durable access in the arm that takes weeks to mature. Instead, a catheter goes into a large vein in the neck and dialysis starts within days. A person's entire life lurches—along with their family's—as the machine clears the blood of waste products and prevents disaster. Hence the term crash-start, coined by the technicians who do the work. Roughly 25 to 40% of new dialysis patients face this nightmare.
Often, through no fault of their own, they simply had no idea anything was wrong.
Your primary care provider should be completely up to date on the various wrinkles in detecting it early. If you don't have one, don't let high blood pressure or high blood sugar go untreated. Get medical help.
Kidney function declines with age and, most of the time your doctor can deal with it. Testing kidney function is like using a seatbelt; hopefully it won't be needed on your particular trip through life, but kidney failure is like an auto accident—nobody is going to put it on your calendar.