How long does it take to update an ipod touch 3.1.3 to a 4.3.5?

To update your iPod touch (4th generation), the current update is 4.3, it says that it takes approximately 3 - 4 hours. You may be best off updating it at night, and make sure that you plug in your computer. Hope this helps!!!

Right now Im downloading mine and its been in for about and hour i think so yes plug in your computer let it do it maybe overnight but remember dont unlock your ipod and dont shut down your computer!!