used to be a lot less frequent.... with the stock wicks. With cotton, I can tell if it is over a day old. Seems like between my wife and I, I am forever recoiling wicks. I went to SS. Kind of a pain in the ViVi, but worth the effort. More flavor, and no burnt cotton. I have the AGA-T2+'s on order though. Time for the next best thing I guess. Over 4 years I went from C2's to Nova tanks, to ViVi Nova, and now I am going to tinker with the AGA. Good luck!