I took 2 T of ACV in a large (16 oz?) glass of water each morning for over 2 years. My hope was for helping joints (I have lupus). I started it and continued, although I never saw a difference in regularity, joints or any of the other promises. One day, when my bottle ran out, I simply didn't buy a new one (ACV) and I haven't returned to it because I noticed -- again -- no difference!
Perhaps some people are missing something from their daily nutrition, therefore benefit from it? I like eating veg (and I take Shakeology supplement, which costs a fortune but every time my Naturopath friend suggests I take something, I look and it's already in there ;p ) and raw nuts to keep me regular.