It is easy to perceive IT as a discrete area of operational support, and forget that “IT” ecompasses an exceptionally broad range of areas. Many specific areas of IT have little to do with one another.
It is easy to think that a highly trained IT member is knowledgeable about most areas. That isn't a realistic view of the technology support role in any organization. Except for very large organizations which have deep pockets, it can be difficult to support your IT infrastructure in an optimal fashion because there are so many different things that need to be handled.
A business’s IT infrastructure is not monolithic. IT encompasses a wide range of areas of expertise. An individual skilled in networks, for instance, may not have the necessary background to support software applications or VoIP. As a result, to optimally support all of your IT, you need a IT support staff that includes individuals with different skill sets.
In a very large organization, that is feasible; however, in smaller organizations, the lack of economies of scale make having a fully staffed IT department economically impossible.
As a result, your growth may be impeded because of a lack of depth in the design and support of your infrastructure. Some things just don’t get done, or at least don't get done as well as they might. Also, without a depth of available support, your business may be less able to quickly recover in the face of a disaster.
Also, one concept that underpins all of your IT infrastructure is that it must be available 24/7. Unfortunately, most organizations cannot afford a full cadre of IT staffers 24/7 and that leaves them vulnerable. They are less likely to immediately identify an issue, and be less able to respond with the immediacy that is required.
A MSP can be brought in to supplement specific areas where your business cannot justify full time staffing. A MSP is also able to provide 24/7 monitoring and maintenance at a fraction of the cost compared to having 24/7 in-house staff.