Tech support is a high priority need for many companies.  This becomes an inherent need once a company exceeds 100 employees.  Every day there will be a certain amount of tech support issues that come up with each desktop that you have in play.  At 100 employees there are enough computer problems to keep a tech support employee busy.

An alternative to this would be to outsource your tech support needs to a company that charges by total employees.  At the end of the day, the cost is going to be about the same.