How often should you change the filter on your... (by 2 users)

I have the service manual for your air conditioner. As far as how often you should change the air filter depends vairies dependnent upon the conditon of the filter. As far as on cleanble filters how often you should clean the filter such as the front filter on your air condtioner varies depending on the size of dust that goes through it and get stuck in the filter and how dusty the enviorment in the area of the air conditoner and how often you use it. I was going to be buying an optional air filter called the plasma filter assembly for an LG model LB1200ER air conditoner however my service manual which covers yours and my model does not give me a part number for this rear filter nor bracket that hods the rear filter in place however the parts that it comes between are the same part numbers as on the LW1200PR so I figured out I believe the rear filter part number though have no information on the bracket part number that holds the rear filter in placed called the plasma filter assembly. Though the part number might be on the bracket on an air conditoner supplied with this bracket. If you give me an email address I can email you the serivice manual that showss a picture of he bracket and best if you could also give me a telephone number and paper mailing address. Could you please inform me of anything and all it says on this bracket you may have to remove the bracket to read everythinbg on it, also please inform me if it does not give any numbers nor say anything on the bracket. I could pay you something for your help if needed. Sincerely, Steven Bolin
2851 SW. Yancy Street
Seattle, WA 98126-2543
(206)937-2467
wizard24672000@yahoo.com