Exactly my question!!
Thanks

It really depends on the fixture, height of ceiling, and if there is a view on the other side you might be blocking. Many people try to claim that 30" above a table or countertop is the rule. As an electrician, I have hung thousands of these. When in doubt, I usually go by this rule so I don't cut the wires too short. But, when the owners come to look at the lights after work, I usually have it scheduled to stick around and raise them while they are there. I would say that less than 10% stay that low on an island unless they are small and unobtrusive. Usually, they end up being at whatever height the tallest person in the family can see under them and feel comfortable standing at the counter and working. It is just a put them up and see what works best kind of thing.

Thank you Fred S your information was very helpful!