The key asset that you create is code, so you really, really want to keep it safe and make sure you do not waste your work and time.
You have been very intensively working on a new app throughout the whole week. By Friday your app is already in good shape and the basic functionality works. Over the weekend you have got some clever ideas, made some changes to the source code, and it is Monday morning in the office and nothing is working. You wish you could move back in time and put your app in a state when it was last working. This is what version control is all about. Every time you make a change to a source code file, or any other asset that belongs to your project, this change is saved and you can easily roll back ...