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).

You are required to be solicitous and helpful if they ask for help with something (move your car or kennel your dog). It would be nice of you to have a cooler full of water bottles and if it's cold, hot coffee. 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.

If the crew really knocks you out with how awesome they are you can follow your heart and open your wallet but don't think there is an obligation beyond normal niceties.

Providing water is nice. But they are expected to take care of their personal needs unless pre-arranged otherwise. They are being paid so they can buy things like food.

I generally set up some drinks for them and that's it. If I really like the crew I'll get some chips for them.

We got takeout lunch once for movers (not a full day) because it was convenient as we were already getting for ourselves, but otherwise I've always thought they'd prefer to leave and take a real break (and also often need to go to the store for something anyway). Maybe if there isn't any local takeout place nearby I'd offer something. It's good to keep in mind.

I'd always feed the contractors when they work at my place. It'll provide a bit of extra motivation to get the job done well.

I don't know what the norm is. If they're working on Saturday or Sunday, I buy a bag of tacos for all of us. On weekdays, i do nothing. Sometimes i set out a cooler full of waters.