Why do we track the different phases of the moon?

Question

I'm doing a report on the moon and this is 1 of the questions.

Answer 1

Nowadays, the best answer is because it it there.

HISTORICALLY, many societies used a lunar calender.  So it was important to check where the moon was to know when it was the start of a new month..  

For instance, the Jewish calender is based on a 19 year cycle of 7 leap months (13 MONTHS) of 383 or 384 days and 12- 12 month years of 354-355 days.  The Muslim have a similar lunar calender, but don't do leap months.  

Another more practical reason is to know when strong tides occur.