Aircon Filter ~ need to change?

[vividance]

Hi,

I have a S13, ca18det . recently my aircon compressor had its time and decided to take a rest. I send it to my mechanic and he reckon that I should change the air con filter as well as it's dirty.

is it true that aircon filter needs to change.

What i am talking about is the round tube which has a see thru glass. The glass tell you whether or not the aircon gas is full.

Anyone reckon that it need to change?
how much would it be?