Some large organisations, including the NHS, choose to completely outsource their IT, so that a company made up of IT consultants based elsewhere geographically, and acting as a separate business, becomes the organisation's IT department.
This can be particularly beneficial if the requirements are beyond the technical abilities of the current staff and management.
It's also beneficial if you're unsure as to whether an in-house department with IT consultants is financially viable, because with outsourcing, each individual hour is billable and accounted for, and so labor hours are transparent.
Outsourcing will also utilize a wide variety of people and knowledge at an IT firm, at a lesser cost than maintaining a whole department of IT consultants in-house, where you would be paying full-time salaries whether expertise were needed eight hours a day or not.
Specialist IT staff are notoriously hard to retain, as they are constantly head-hunted by money-hungry specialist IT recruitment consultants.
You also won't need to worry about organizing and paying for training for staff on the latest technologies as an outsourcing company will be at the forefront of this.
Another benefit with outsourcing is that as an employer of services, a firm will be intent on keeping your business once it has secured it.
There is generally less chance of complacency as there could potentially be with in-house staff, as you could easily take your business else where should you be unsatisfied with performance.
Outsourcing to IT consultants makes sense in some modern, online businesses, even if there is already an in-house IT department, because it offers the management the right climate to be able to focus on the goals of the business.
For example, a highly-competitive business at the cutting-edge of product launching may find that a new IT application delay can throw a spanner in the works and delay route to market, thus losing them the competitive edge.
If the in-house department is constantly busy with routine queries and problems, it won't have the time, and possibly the expertise, to quickly rectify the problem and clear the path to market for the new product.
Different businesses have different IT requirements, and you may find that a mixture of both in-house and outsourced IT works best; with outsourcing used for very technical and up-to-the minute specialisms that it wouldn't be financially viable to maintain an in-house team for.
A good IT firm can work with you to establish the best way of working for the needs of your individual company.