Coming from an IT, and Data Warehosuing background, I highly recommend optional text boxes for anything you might have the remotest interest in analysing by in the future.
Its much easier to give someone a liink to a phase of moon calendar and ask them to include the phase of the moon than to go back and add moon phase after you have been up and running for a long time.
Obviously, you won't know up front every factor that you wished to include, but the more thorough you were in planning up front, the more valuable your data would be.