the tanks will last forever if you don't break them. It's just a removable plastic resivour. No filler or anything like that.
Janty batteries are warenteed for 6 months, and attys for 3 months. (try finding that anywhere else) But they'll last a lot longer than that if you take care of them.
I really think you'd like bloogs better, to get you off of analogs. They also have a 100% money back garentee. And their customer service is awsome.. just ask if you have a problem, and they'll make it right. I recomend the mini, as it's the closest size to a real cig. the batts will last anywhere from 2-4 hours, but thats why you get the PCC (personal charging case). it's really small, coolest design of any others out there, and will charge your bat about 4 times before having the recharge the PCC at night. It will last you a whole day. And just your luck, I believe the mini kits are the only ones instock right now. Everything keeps getting sold out as word gets spread around about how great they are. mini kits are only in stock becuase they got a large shipment in a couple weeks ago.
The bloog cartos seem to last forever also, I started a thread/experiment in the bloog subforum, about how long they last. I've been refilling two cartos, using only them every day, for over 3 weeks now. No one really knows how long they last yet, because they don't fail often.
I don't want to sound like a sales person or anything. Do some more research. Watch a few youtube reviews. You won't be disapointed with either Janty or Bloog, they're both industry leaders.