Headlights have several working elements. You have high and low beams, brake, and turn signal lights. The electrical socket and wiring are prone to corrosion over time. Cracks in the lens can allow water entry that will accelerate the process. Many times, you can get away with 2006 ford E350 headlight bulb replacement, but if the damage is beyond the bulb a new assembly will be needed. When changing a headlight, always look for a blown fuse. Even if a new assembly is installed Ford E350 headlights won't work if the fuse is burnt out.
Ford E350 headlight removal doesn't typically require a mechanic. All you have to do is remove the screws, and take out the clamps from behind the hood, and the assembly will come out. You can access the bulbs and the wiring this way too. New headlight assemblies are also easy to reinstall. Doing so DIY style avoids the costs of labor and other fees from a mechanic. Oftentimes it will leave you only with the cost of the part to worry about, which is often not all that much. Still, there is significant variability among suppliers and the types of parts available for your vehicle. Do your homework if possible because you don't want to spend more than is necessary.