It depends on the Qi liquid's interaction with the EMF, the more EMF around, the more of the Qi liquid is being used. For example, if there are less than 10 sources of wifi in your home, the Qi-Shield should function optimally for 3-5 years. If you have more wifi than that, the function of the Qi liquid will diminish at a faster rate. Also take into account your living environment such as apartments, neighbors wifi, cell towers nearby, etc. as well as any future potentially stronger rollouts such as 6G and beyond. Lifespan of each: The Qi-Shield will last up to 5 years, but we do not offer recharge on these smaller devices. Instead, we are happy to offer a discount on your next device purchase. The Qi-Home Cell and Qi-Max Cell will last up to 8 years, before needing to be recharged.