The main disagreements are in the feeding schedule and tank cleaning. One site I read they only need to be fed once every 3 days as they will continue to eat if overfed where as another says 2-3 times a day and yet another says once daily.
One site says that a full tank cleaning is needed only once a month with 1/3 water change weekly and another says full tank cleaning is needed every 5-7 days.

I googled Betta fish care so I didn't retain site names. I was just needing experienced owners advice and/or narrow down the sites to read.