What is mental build-up for a project

We need to keep the feeling which motivated to take up that project.Mostly,we do not begin a new job which was inspired because we are always doing something or other and we are in the middle of some earlier project.So,by the time we have time on our hands we do not have the mood on our mind,the desire to take up that job has faded away with the feeling which motivated and inspired us in the first flash