Would agree with three batteries minimum, if you can charge on the go with inverter or 12V charger you could more or less keep going indefinitely if need  be.
Trouble is once you half use a battery, you can't do anything too ambitious so you don't get to use the full flight time very often.
As above they have progressively got easier to fly and harder to crash, if anyhing the risk is getting over-confient early on as things can still go wrong.
The tricky part at first is being aware that the orientation changes the stick behaviour e.g. Left and Right are reversed when ithas turned towards you.
This is more of a problem when not looking at screen. 

Way too addictive though ...