I think after 75 it is more usual to have stage 3 kidney disease than not to have it. All my elderly relatives did and in none did it require treatment or impinge on their other co-morbidities. Its important to distinguish between kidney disease & kidney failure. Disease means that there are signs on your blood tests or biopsy that your kidneys are not functioning perfectly. Failure means that your kidneys cannot quite cope with their job & are not removing waste as they should. Failure is more worrying. Drink plenty even when you feel unwell or you're temporarily immobile, & be very alert to any signs that a cold or virus going round is making you feel rotten (temperature, lightheaded, breathing more laboured) and also remind the GP if you're prescribed new medicines, that you have stage 3 kidney disease. These are things (dehydration, sepsis, nephrotoxic drugs) that could send you into kidney failure,which does need prompt treatment.(rehydration usually, not dialysis) & is usually reversable back to your current stage 3.