If you live far from your ancestral homeland, it can be tempting to hire someone to search an archive on your behalf. Even though any historian worth their salt will charge at least $20 per hour, it may, in fact save you thousands of dollars to hire someone, as opposed to flying to the archive, paying for a place to stay and to feed yourself. This is especially the case if the archive in question is small and remote.
But, before you hire someone, consider the following:
1) Do they have experience with the archive?
Verify that the person has done this before in this exact archive. It takes time and experience with an archive to know what is there, what's not there, and how most efficiently to work at that location. If you're paying someone by the hour, you'll want them to be efficient.
2) Are they overqualified?
Chances are you're not going to get a world famous historian to research your family history for you. And, if you do, ask yourself why. Many professional historians teach, research or write books full time, leaving them with no time to take family history gigs. In the case of university professors, they get paid far more in salary than you'll likely want to shell out. If they do agree to work for you, make sure they aren't trying to use their title or reputation to scam you. You'll likely get higher quality research and more attention from someone who specializes in family history research (for less money) than someone who thinks, 'sure, I'll take this guy's money and charge exorbitantly' and produce little results.
3) Do it right the first time
If you're going to hire someone, make sure they do the WHOLE job. You want them to give you every morsel in that archive so that you or anyone else in the future never has to go back looking there again. It is very difficult to pick up someone else's research without knowing exactly what they've looked at already. If they know the archive contains nothing else, that will save you time and money later.
Hiring someone can be rewarding and save you money, but don't be fooled by fancy titles. Hire someone who does this every day.