Where do you draw the line in what you will and will not take a medication to alleviate?

I will only now take my hypertension medication and an occasional pain reliever. I had a sister in law that did not feel that she needed to take her seizure medication because she had been seizure free for 16+ years and she ended up dying from status epilepiticus at the age of 31. I feel that I am confident in my physician's prescription and know that if I am not on a maintenance medication for my hypertension I would be adding more stress to my heart and kidneys which will ultimately kill me a lot faster than an occasional headache from taking my medication.