I personally feel that a residential landscape project is never really finished.

Plants and trees grow. Their shapes and light requirements change. Some plants may be blocked or covered up by other ones, and revisions may be needed.  Plants are living things and like us, change and grow.  When I install a landscape I plan for space to allow the plants to grow.  I don't want to leave a client with a landscape that will look crowded or messy in six months.