A lot of people have risen this question and have complained a lot about it. When you are buying an air purifier, it is never guaranteed that for how long the replacement filters will be available in the market. Companies keep upgrading their air purifiers every other day and keep replacing the old technology with the new one. The new filters are then often not compatible with the old technology, and that creates a big problem for people who have the old model of the air purifiers. One of the solutions to these problems is to buy the latest version or the latest model of the air purifier, which is available in the market, as the company will not be cutting all the supplies of that product for a long time. You will at least then have 2 to 3 years before something new comes in. The next best thing you can do is buy some extra filters. When you are making the purchase, you are pretty much certain that you will have to replace the filters every three months or every 6 months. To avoid any inconvenience afterward, you can buy some extra filters to be used later. You may not use those filters while they are still available in the shop and after the company stops manufacturing them, you can pull out the old saved ones that you had and work with them. You can also search for other shops, which have things related to this as they might also have saved some of such material for later use. You can keep buying from them, and your filter and air purifier will work fine.