The easy answer is spring and fall. The better answer is fall. This is because all of the weed seeds in your soil have likely germinated by now, or will be going dormant as the season starts to cool down.
What this means, is that any disturbed soil, bare soil, etc, will not produce as many weeds as the spring time seeding will, giving your grass seed a better chance of establishment
Yes, we carry all necessary insurance and licenses, including our pesticide license.
What this means, is that we are able to look at your lawn, and decide whether or not the lawn is salvageable. If it is inundated with weeds, we are able to treat the weeds to allow better establishment of grass

No, we do not need to bring any heavy equipment on to your property. With over 300' of hose, we are able to park on the road, or in your driveway, and reach any area, leaving the rest of your yard intact.