Do you find this chart to be accurate?

http://www.wilton.com/decorating/fondant/fondant-amounts-to-cover-cakes.cfm

I'd like to know how much fondant to roll out as I am not too experienced using it. Or do you just grab some and if you have too much, knead it back in with the rest?

Also, how long does fondant last in the tub? Thanks

I use this one.

http://www.earlenescakes.com/Fondantchart.html

Fondant lasts a long time if properly stored. I haven't ever had a tub go south on me.