I have a Lennox system. It is variable speed fan and a two speed compressor. Recently upon my annual inspection my tech said the handler fan blower was dirty and proceeded to sell me a package that involved him removing the blower to clean in. It also involved cleaning coils both inside and outside as well as calibrate the system and replace any capacitors or wire ends that were corroded or needed it. My system seems to work ok but the dirt on the fan I nasty. The system is 10 years old. My question is, should be be done as normal maintenance or is it unnecessary? I ask because it's quite expensive but have no problem with it if it's standard maintenance for unit and personal health.