Detailed warranty policy is stated on a product page.
Mods and batteries have 60 days warranty,
tanks and clearomizers have DOA warranty policy (Dead On Arrival),
Replacement coils come without any warranty,
RBA, RDA, RDTA - all kinds of rebuildable tanks have DOA warranty, you should check them when they received, and they do not have any kind of human error warranty, as these designed to be builded and rebuilded by expert users.