Why does your company need IT Support?
But consider what your IT systems do for your company: you have a team who are all being paid a salary. If their roles rely on computers and a network then they simply can't do their job without it. If that setup is running even slightly slower than it should you could easily lose 20 min a day waiting on a report to run, pc to start up, document to print etc etc.
If this happens to say 10 staff who get paid £8 per hour that works out at 20min x 10staff = 200min per day x 5 days per week = 1000min downtime or £133 per week @ £8 per hour. That doesn't even take into account major failures or data loss, not only do you suffer loss of goodwill from your clients, but the frustration that staff can experience can add to stress in the workplace.
So what relevance is this to IT support and management? In simple terms, if the job is done correctly - a lot of the time using only your existing equipment, your get a reliable and efficient network at a reasonable cost, serving the functions your staff need to perform their duties.
Trying to employ an IT person who understands the entire scope of their business is difficult and time consuming and can cost you a lot of money. The range of skills required to manage a network and support it is most often the work of a team of skilled engineers, not just an IT bod. Employing a single person to the role will invariably leave you short of some critical skills.
Often businesses choose to purchase their support from a single person. The problem will become apparent once you have more than a couple of things to fix every month, or if you have something that needs fixing urgently, there are plenty of reasons why aproaching an IT support company makes sense.