There are things in business that can be outsourced and some that should be kept internal. What you do with your IT support depends a great deal on what your company structure is and what your budget is. So do you hire or contract IT support?
If you are sitting with a lot of users and a lot of IT equipment, you may want to look at hiring your IT support. They will constantly be onsite and be available to fix a problem the minute it crops up. Of course, you may not have problems very often because you only hire tech savvy people… In this case, contract IT support, but get an SLA in place. This will give you preference over ad hoc clients with the company that you contract in.
In the event that you have a few computers and users and seldom actually use those computers, the best bet would be to contract IT support. It is unlikely that you will have enough work to keep a full time IT technician busy but you will still want to get help when you need it.
Another instance where it would be better to contract IT support rather than hire new employees is if you are doing a large IT project. You would do better to contract IT support for the project because the project is going to come to an end. Once the project is ended, what do you do with all the people you hired? You could retrench them, but that is really expensive. It is unlikely that you are going to have enough work to keep them all busy though.
In short, unless you have a lot of users and servers and various other pieces of IT equipment, the option of hiring IT support is not really a viable one. An IT support contract is far more cost effective and can be made use of when needed rather than facing the situation of bored employees. Think carefully before you hire IT support. It is very likely that to contract IT support would be a better option.