Today I received a letter from BT Solar ltd.  They say that my inverter warranty has now expired, correctly, and a health check and service is required to validate the warranty.  I wonder how many people fall for that one.  But just out of interest, is there really anything in an invertor to service, and how would they go about doing a health check.  It either works or is doesn't, surely?  And what is a good life for an invertor?  We've had our Sunny Boy for seven and a half years.