When you are not in close proximity to a friend, you have an excuse to not keep in contact you forget that your friend existed you no longer have to treat your friend nicely when you do see each other staying in touch can be harder

staying in touch can be harder.

Explanation: There are many factors that should be considered when answering this question because not all the friendships are the same. However, in general, when you are physically away from a friend for a lot of time it tends to be more difficult to stay in touch. You are not part of each others lives and you do not need each other as much as you used to do.

You are not violent and you do not forget each other.

is there a year set? the question is incomplete