Why/when should you hire a mortgage broker?

[Peter K.]

Looking at what they do vs. how much you pay. I think the cost-benefit analysis shows that if you are able to do your own research and shop around, you can certaintly find the lowest rates for a home mortgage as opposed to paying a hefty fine (usually around 1-2%) by using a mortgage broker. Someone explain to me when/why should you hire one? Examples would be great. I'm still convinced I can do my own research and will never use one. Want to hear the flip side to it.