Texas

You are not required to provide lunch. You are not expected to tip. You hired a service and you're paying for it (I know your new windows weren't cheap).

For real. But I'm looking forward to it getting done!

You can also offer snacks or comfortable seating (lawn furniture set up, perhaps) if you want to impress them with how much you appreciate their work.

I like this idea. I dunno how many are coming out, but I have a couple of newer camping chairs, and we've got a cooler, so we can do hot or cold drinks.