Hello All. I have 2 Philips Series 9 shavers that I alternately use. I find the cleaning station cartridge has to be replaced about every 2 weeks if that. I was on a cruise ship for a month recently and only brought the one shaver and one cleaning station. To my amazement the cartridge lasted almost the entire journey. I was starting to think that perhaps there was something wrong and so check the level of fluid periodically and it was always fine. Just wondering if anyone had any thoughts as to why this would happen?