Generally about a tbsp with a cup of water. Timing is usually before bed and/or 10 minutes before eating.

It depends on what you're wanting to get out of it, @freckles2002

If you're going for the probiotic benefits, I think the recommendation above is consistent with what I've heard. Make sure you get a brand that is "with the mother" and preferably organic.

If you're going for digestive benefits, it's 1-3 tsp diluted in water at the beginning of the meal (if you can't do before). For me, that's not enough, and I have to include digestive enzymes, and due to the volume, I switched to the pill form for the ACV. On particularly difficult digestion meals, I even add a Betaine HCL supplement separately.