New commitments will often cause your members to fade away from the community.
Don’t let that happen.
Have a proper farewell to members that are leaving. Encourage people to let you know when they don’t have time to participate anymore. Create a farewell post for them. People can add their best memories of that person.
Make a tradition of doing it. It tightens the community and encourages people to build up relationships during their time. After all, nobody wants an empty post.