Somewhere around Day 5 of shooting and then once again around the halfway point in editing, you will have a realization that this film is a lot of work. At that point, you will either be encouraged to think how worthwhile the project is or will be completely deflated to think of the huge waste of time and money you are in the middle of. Your response will be determined primarily by how good your story is. Do you have something that is barely passable as a movie--or do you have something that will move, inspire and thrill people?
There was a time (only a few short years ago) that you got credit for trying. What I mean by that is that anyone who was actually able to turn out a finished film was lauded and people would watch it. I remember going to a screening about 12 years ago for a film that a friend of mine had helped finance. They were all raving about it, but when I saw it I was thoroughly embarrassed that I was even sitting there watching it. The tools back then were not as inexpensive as they are today, so it was not a cheap production. The story was so weak, however, that it was truly a waste of an hour and a half. Afterwards, everyone was congratulatory of the filmmaker and were honestly excited that they were a part of the project. I assure you that this is not the case anymore. With the number of indie films released each year, and a very large number of them with pretty high production value, it takes a great story and an interesting premise to even get people interested. Major Hollywood releases are even taking huge losses these days when they do not connect with people on some level with the story.
The lesson in all of this is to make sure you have something great before you commit a large part of your life to it. The least expensive stage of production is the writing stage, so take the time to find or develop a script that you can be truly excited about and that you know will connect with your audience. If you do, then you will find the strength to press on when the process of making the film turns from fun to work--and it always will at some point.