When traveling in the States and especially overseas there are items that are in your best interest to carry with you. Take along a list of your medications and prescriptions, eyeglass prescriptions, allergies and key health information. RAO Aug-Oct 96. Moreover, some of those countries require applicants to pay in cash. Watch where you obtain your visas.
Some agencies charge outrages prices for the service - shop around.
Its always best to do it yourself. If you plan to go make sure you arrange through a reputable agent. Too many can't follow thru on arrangements and tours. Applications are available at major post offices or courthouses. The travel documents remain valid for ten years.