When do people invest the time to input data into an information system?

If you have confidence that information you put into the system will be useful to you in the future, then you'll do it.

Even better if you have confidence that it will become more useful the more you put in, and the more powerful the system becomes.

The lower the overhead and annoyance of putting information in, and the more likely something useful comes out later, the more you'll be willing to invest time in putting things into the system.