How much juice?

How much juice do you personally give your toddlers? I have a 15 month old, I tell my husband all the time he isn't supposed to be having juice unless it's prune juice for constipation bit he thinks I should still give him apple juice sometimes because he 'gets bored of water' because sometimes we have a hard time getting him to drink enough water.

What are your personal preferences and rules about juice? I'm trying to keep him as healthy as possible and follow guidelines but my husband and some of my friends say I'm being stupid.

And yes his teeth are brushed twice a day