It's been many years since the earthquake, but because of ongoing social, economic and political problems, Haiti is struggling to support its own people, as are relief agencies to provide for their own personnel. If you are considering traveling to Haiti to aid in relief work, make very sure that you already have a position and that they actually need you.
Make sure that regardless of whether you are doing paid or volunteer work, that the organisation you are planning on working for is able to provide the basics of food, water, accommodation, security and transportation.
Check to make sure that the organisation has a security plan in place both for preventing you from getting into serious danger and getting you out safely is something happens.
Hotel space is remains limited, so once again, check and make very sure that the organisation you are planning on working for can accommodate you.
If you do intend to do relief work in Haiti, either paid or volunteer, full-time or part-time, you will need specialist travel insurance, your regular policy will probably explicitly exclude relief work (read the policy and the PDS carefully). If you have any doubts, give your insurer a call.
You can buy at home or while traveling, and claim online from anywhere in the world. With 150+ adventure activities covered and 24/7 emergency assistance.