It's polycarbonate that has problems, polypropylene is a different plastic. I have a banana juice that I'm working on and the banana flavouring I'm using contains one of the big track cracking compounds. I've had an RSST tank sat half full of this stuff for over a couple of weeks and no issues with it.
A genesis coil will last a long time before you need to replace it. It'll need cleaning regularly, how often depends on the juice you use and the power you're pushing through it. The coil will last until it physically breaks which could be weeks. The wick is reusable many, many times, you just need to rebuild the coil when you replace one you don't need to redo the wick each time.