What’s wrong with the 15th

[Rousner E.]

This may seem stupid but, what’s wrong with having rent due on the 15th or any other day? Is there something I’m not thinking of.

[Dick Stevens]

You can have rent due any day you want, just document accordingly in rental agreement.  If you have multiple properties though, it’s easiest to be consistent with the day rent is due for ease of record keeping.