You need to watch the twins to see how things work, and the twins will tell you what is right for them. Most of my research suggests that identical twins enjoy being twins. Most of the twins that have been in my study enjoy being twins. As much as twins like being twins, they tend to be sensitive to their differences. I think it is important to bring fraternal twins into this conversation.
Fraternal twins enjoy being twins for the most part.
It is a special relationship, but they don't show the same relationship as identical twins. Fraternal twins don't get along as well as identical twins. If parents are worried about this, you don't need to be so worried. The children are expressing their own individual styles. One of the hardest things that any twin goes through is the potential loss of their twin.