When a customer looks for a cleaning company they are looking for the best solutions for all of their cleaning needs.  Many times the offices and commercial buildings I work at have carpet that needs a semi-annual cleaning to get rid of high traffic patterns and general grime.  The customer does not want to shop that service as well, they expect anyone they hire as a cleaner to be able to clean whatever is in the building.  Simply put, they expect their cleaner to be able to clean their building top to bottom.

As the cleaning business my clients hire I have two options, sub out the work or to do the work myself.  Hiring a sub-contactor is an insurance liability and also puts money somewhere other than my pocket.  Doing the work myself is rewarding not just financially but also as a matter of pride.  Educating myself and learning a trade keeps me from losing future business.  Not to mention having to apologize for a subs lack of personal care.  If they do sub par work they don't have to fear losing an account that they did not have to work to gain. 

In the end, I would want my clients to view me as a one stop solution to all their cleaning needs and that would include their carpet cleaning also.