If it's the same as iEra, about 1-2 months.

Please tell me iZone wont require regular commitment to play a lot like iEra does. If you quit iEra for a month you find out all your weapons are rusty and you need to mine a lot as well as grind a bunch of money just to get back on your footing. You also need to pay $1000 a week for unlimited revive and ammo. The 2 hour daily bonus did help a bit, but its kind of annoying when you log on just to see if there's anything new, then later log on and your daily bonus is gone.

I really hope iZone doesn't require commitment like iEra does, its the only reason I prefer Classic over era(well that and because all my friends play Classic and iEra requires insane grinding or real money to compete).