Yups. It's true. If your juices gives you a clean vape, the SS mesh can last for months.
But. Your question of "Any idea how long should I keep my juice in the atomizer?" only applies to vape once in awhile, in which case, try not to keep it in the atomizer for too long. 1 week, okay... 2 weeks, maybe... 3 weeks, hell, I wouldn't risk it.