How long does the production stage take?
The only reasonable answer to this matter is that it varies from production to production.
There are certain key principles you can apply and that will make your life much easier during production.
TIME… DON’T STRESS ABOUT IT, PREPARE FOR IT
If you are doing a story that you love and that motivates you enough, time shouldn’t be a problem. Inconvinients will always happen so the most reasonable thing to do when you are faced with a difficult challenge involving time is do not stress too much about it. Motivation and euphoria is a good kind of stress that pushes yourself to overcome pressures and yourself for the sake of a certain goal. Stress is another and very different thing. Stress will paralyze you and get the worst out of you without getting any work done.
Imagine you have to film a number of scenes before you and everyone else goes on hollidays you NEED to finish filming those scenes because if not you do not have the certainty you can finish them after two months away and the deadline of the film festival entry you are interested due in September.
The truth is that the battle against time is rarely won and you need either of two things: disponibility and money. And both of those means money. Money that most independent filmmakers do not have.
So how can I manage my shooting time?
Do not stress about it and methodically solve the problems that haunt you in a sportive way.
For example, if you can finish shooting before vacations even if that means putting in double of work if you truly believe that the film being finished before vacations it’s necessary.
If you think you can with hard work and persistence finish it after vacations and you can hustle enough to get your film on another and better festival, that might be your choice. If you can even get your film into a festival that is almost due time because you someone in the industry, do that definitely.
Then again is about analyzing your situation and giving it a reasonable solution.