Too many times I've seen threads about DP's / Beta's have been installed on normal production (day-to-day use) machines WITHOUT a solid back-up routine. When things go wrong they "Blame it on the Boogie" 
Back-up before you install any DP or Beta release over an existing working version of OS X. Better safe then sorry! Just my 0.2ct.
Enjoy your beta release of OS X Yosemite!
~ Cheers
Back-up before you install any DP or Beta release over an existing working version of OS X. Better safe then sorry! Just my 0.2ct.
Enjoy your beta release of OS X Yosemite!
~ Cheers