I use it as a 10 filter "to get the most out of it", as soon as it starts brewing you can tell it's starting to work, as time passes the coffee gets stronger and darker so it needs to be changed.

I change it approximately every three months and the main one every year, I notice that after three months it has already turned brown.

I don't know how others used it, but I have it as a third filter in the tank (the previous two are larger in size) that I have for drilling and it filters very well. At least visible dirt or particles do not pass through this filter. Since I put it, not even the smallest grain of sand or anything else has entered the tank. I have been using this filter for 8 months.