Don't use sharkbites to do an entire house, it will be very expensive. Rent the tool to crimp. A half inch shark bite will cost you at least 5 dollars a fitting. Just crimp it's the cheapest way to go and the best.

This is from the pex installation guide. Pex pipe should be anchored down every 32 inches on a horizontal run and every 4 foot on vertical runs. Here is a link to the manual. http://www.siouxchief.com/Resource_/ProductMedia/115/PEX%20Installation%20Guide%205-05.pdf