1. Is the task a primary service or offering of your business?
Don't waste valuable time on something that isn't your specialty.
2. Is there a competitive advantage to doing it in-house?
Unless it advances your company, using an independent contractor may be more beneficial than hiring staff.
3. Is it a specialized service you don't need to handle full-time?
For example, you might have only one event a year that requires event planning support.
4. Is it a commodity--a task some one else can do better and more efficiently?
Workplace cleaning and floor care is an example of such a task.
5. Are the costs of the service lower than what it would take in time and manpower to get it done in-house?