After vaping for over 3 years I have just about tried all there is in vaping gear!, but I would have to say your parents are extremely lucky or very light vapers. Even your own atomizers lasting 4 to 6 weeks is good.
My atomizers rarely die as such but the performance becomes weak, and now the cost of the eGo-C atomizer is down to £4 each I don't even attempt to clean the atomisers beyond the occasional blow through, I bin mine after 3 to 4 weeks. A running cost of around a £1 per week seems reasonable to me, I could however suffer poor performance for many weeks more before the atomizer would die completely.
The Titan tank atomizer will run quite happily on the Tornado battery, and if you got one of the original Tornados (prior to the tank system) you may have the cover cone which will make the set up aesthetically pleasing