A principle that applies to both professional and personal life is summed up nicely on a post I ran across on “The Rat Race Trap” blog. In short, not every activity that you can perform should be performed by you…it may create value but if the cost of that value exceeds the benefit and/or if there are opportunity costs to you performing that particular activity (i.e. if there is something else you could/should be doing that would create more value) you should pursue another activity.
Check out the blog post for a much better explanation than others I’ve read before. Additionally, there are some other great posts on the same site you might find useful: