I've been getting estimates on 15,000 mile service from dealers here in San Diego and they run anywhere from $190 to $240 and they all include a new cabin air filter at $60 to $70. Just how necessary is the replacement of that filter? My '93 Subaru has 140,000 miles on it and has never had any cabin air filter replaced (if it even has one). Also, even without the filter the service runs $130 to $170 which seems awfully high. The 5,000 and 10,000 mile services were only about $65. I don't have my book handy right now (wife has car) but I don't remember reading anything special about the 15,000 mile service. Finally, any thoughts on having the service done by a non-Toyota shop?