I bought a brand new haze a month or two ago, I have been using it daily for dry herb only and the machine is great.
I did buy extra batteries too but I have barely used them, what comes in the box as standard (2 batteries, 2 cans & 2 screens iirc) is honestly more than enough kit unless you have decided you no longer need oxygen and are just going to inhale vapor all day long
I will use 1 battery on 2-4 cans depending on how I pack them so having 2 batteries as standard means I have plenty of juice for the day. I re-charge the batteries every night too. I am happy I have extra batteries but they are not really needed imho, what comes as standard is more than enough