you can do many things in life yourself, but usually it's best to hire a professional... do you do your own taxes? or work on your car yourself like Rochard pointed out? probably not... professionals have all the right tools, have years of experience, know all the tricks and pitfalls, etc...
with unmanaged server you can kinda wing it by reading some tutorials online, but that would be kinda like trying to replace a car engine based on some youtube tutorial video, or doing your taxes based on what you learned on wikipedia...
