An electronic cigarette vaporizer is not dis-assembled for filling with e-liquid, but is instead filled from a user-replaceable e-liquid cartridge. The vaporizer includes a front section comprising a wick and heating assembly but no e-liquid cartridge, the front section being removably fitted to a body of the vaporizer to enable a replacement front section to be used once the original wick or heating element starts to degrade, that replacement front section being supplied to the end-user with no e-liquid in it.