Completely optional. Need? No. It may be helpful for retaining moisture, though. Just don't put it on too heavy like most people tend to do. Only about 50% coverage. Remember; the seeds need sunlight to germinate. I would be more concerned about the homeowner getting water to it, than anything else.
I tilled up a bunch of dirt, aprox. 2 inches deep and threw a bunch of grass seed down. I goto the property once a day, or 2 out of 3 days to water it. Do i need to put fertilizer down or anything? how long can i expect before i have grass? Biggest concern right now, is i have a bunch of leaves falling over the seeded area. Is this ok? or do i need to get them cleaned up.