We are usually happy to live our lives in a comfort zone, even if we may believe it is not the best, or we could do better. Change is difficult to accept, and therefore change is what we must do to leave our comfort zone.
There is a feeling of renewal in a new beginning, however it is fraught with apprehension of whether we did the right thing. Once we manage to overcome this apprehension we have left the past and really started afresh.
If we are not content then we should try and change again and the cycle starts over again. Only birth and death are permanant everything else can be changed.