We give a lot of time and energy to overhauling our diet and exercise, or perhaps to quitting smoking, but we don't really take a hard look at our lives as a whole. We all have people, groups, and clubs in our lives that may have served their purpose, but we don't realize it because we've never stopped to assess what we want and need in our lives.
Perhaps there's a book club or church group that was wonderful for a long time, but now you find yourself dreading the meetings or, if not dreading, just not feeling the same excitement or joy that you used to when you attended. Perhaps the group has become negative or changed in some way that no longer works for you. It's important to stop and think about how we really feel about the people and the activities we allow into our lives.
It can be very difficult when the concept of "outlived its usefulness" applies to friendships or other relationships with people. It's easier to keep people in our lives and just go along with the status quo rather than really assess the relationship and decide if it is still worthy of your time and attention. This doesn't mean that the person isn't worthy, it simply means that you may have outgrown them or both of you have moved in a direction that no longer suits a friendship between you.
Whatever the case, don't be afraid to carefully and lovingly let go of groups, clubs, and people that no longer fit your life or fit who you are. Nature abhors a vacuum so once you let go of what doesn't fit, something that does will come along and take up that space.