You don't have to be a genius to become a PhD, but time-management skills and sitzfleisch are essential. Visiting an archive tests your ability to sit still for a long period of time and to finish a task in the amount of time you allotted for it.
Most historians have to do a significant amount of traveling in order to complete a research project; few are lucky to have all of the collections they need at nearby archives. For many historians this is a delightful perk of the job. Unfortunately, it's also the part of the job that takes all of your money. The trick is to find that tipping point between expenses and productivity.
Finding aids are a useful guide for evaluating how many hours or days a scholar should plan to spend at an archive. Presumably, you would not travel to an archive to look at only a few documents--these days you can pay a reasonable fee to have archivists scan the materials and email them to you, which is cheaper than booking a flight, hotel, and/or rental car. Most researchers travel to an archive after identifying several collections that they suspect could be useful. The more boxes and folders you plan to dig through, the more time you will need for your visit.
Of course, it's not always possible to anticipate what you'll find. Sometimes a box contains exactly what you expected, other times you open up a folder that you thought would be fat with documents and rich with history and instead all that's there is a couple of notecards covered in illegible scrawl. The worst case scenario is planning a multi-day visit and realizing on the first day that none of the collections you planned to look at are useful for your research. The best case scenario is realizing that all of the collections you wanted to view exceed your wildest dreams!
Even this best case scenario has a downside, though. How could you possibly read through everything in such a short time? Sometimes scholars decide that it's worth it to schedule another visit at a later date in order to finish the work. Then they triage, or prioritize, what to examine first.
If the archive is especially far away, however, or if you are a broke graduate student who cannot afford a return trip, there is still one good option: the "smash and grab"! The "smash and grab" involves taking pictures on your iPhone of as many of the documents as you can in the short time you have available. In this scenario, you do not take the time to check the documents to see if they are particularly relevant. The modus operandi is to take absolutely everything that remotely relates to the project--the irrelevant stuff can be deleted later! The "smash and grab" method is far from ideal, as it raises your blood pressure to unsustainable heights and creates the tedious follow-up chore of processing photos. It's main advantage, though, is that it allows researchers to save some money on the front end even if it takes more time afterwards.
Tomorrow I will go into more detail about what happens when you walk through the door of the archive, how historians interact with archivists, and what reviewing documents actually entails. It will be especially fresh in my mind because I will be spending the next two days conducting research at my main archive in New York, and so I hope to render the whole experience in exquisite detail. Stay tuned.