Volunteers work part-time . Most people only volunteer a few hours a week. So volunteering can be combined with any occupation. It can continue for many years. It has a unique focus on the task.
Volunteers are local .
They come from and serve the local community. They know the needs and the resources. And when disaster strikes, they are already there. Volunteers bring diversity and special abilities. When you recruit staff you can only get those who are looking for a job.