I was working with a web design client recently and once they approved the design, we started building it out. When it was partially finished, we showed it to the client who came back with a great suggestion that will make their site look much better than we originally had designed. If we had waited till the very end to just show the finished work, and then received the suggestion, we would have had to redo a lot of work and charge more for the time. By sharing with the client the work through the process we were able to do better work, have a better finished product and have a happier client.
Be willing to show your work throughout the process, it can be better in the long run.
Have a great day!