How long is "average use?"

[khafan]

Here is picture of filter that I use and I buy it from a shop that sells kitchen hood spare-parts.



I use two side adhesive tape and stick this filter to front of my ps2 like this pic.



Maybe it doesn't look very nice but it's very effective.
I didn't change this filter for about 5 mounths and color of filter shows,
how much dust this filter absorbed.
.