What is the minimum height, I don't want to wind up killing the grass if I mow it too low.

Depends on the season and your climate. If you are in a hot climate or month, the longer the better as it will help to hold moisture, go for about 3 inches. If mild or wet climate, as short as looks good say a minimum of 2 inches.

2.5" probably looks the best. 3" is probably the best for the lawn and looks good. You won't kill it regardless.

1 1/2 " to 2" !! It's pretty hard to kill grass !Even in the summer if your grass goes brown from lack of water it's not dead! As soon as it starts to rain or gets a good watering it will turn green again !! I have cut the grass to low and it always comes back !! Don't sweat it !! Enjoy your lawn !!!

The recommended height is 3".

It does several things.

1. Keeps the grass healthy.
2. Blocks weeds from growing as much.
3. Reduces watering since the ground is protected.

I just started mowing at 3" and my lawn took off. I was having all sorts of weed issues and tried everything. Now I have only a very few weeds and my lawn is growing like crazy.