Question:
Must a Kohen nowadays make sure to take a haircut at least once every 30 days?
Answer:
Such a requirement does not exist so long as the Beit HaMikdash is not standing. See Rambam, Hilchot Biat HaMikdash, Chapter 1, Halacha 11.
http://www.mechon-mamre.org/i/8301.ht
10th of Nisan, 5769 Friday, 03 April 2009