Personally, I stop around 18, though I think it's relevant to consider how many of them there are and how often you see them.
As you don't have children, you might want to carry on for longer if you're close to them, but that's entirely up to you. (you might opt to go for great-nephews and nieces instead once they appear)
no subject
As you don't have children, you might want to carry on for longer if you're close to them, but that's entirely up to you. (you might opt to go for great-nephews and nieces instead once they appear)