Why do I have to choose the amount of days until my project needs to be done?

There needs to be an end to every project, to leave room for new ones. But you can extend your project any time you want.

Related Topics:
How do I close my project, extend it, or pick a freelancer?
What if I don't know what programming language I want my script made in?
Can I re-open a closed project?
What is a budget range?
Can I change the information I provided about my project?
How do I open a new project?
What does it mean if my project is frozen?