We never even warned bottles. Some people were shocked to see us pull a bottle straight out of the fridge and give it to our daughter but I didn’t see any reason to warm them when she was perfectly happy with child milk. I’d rather not have to worry about overheating it or having to lug around a bottle warmer when traveling.
I do like the monitor though but it’s more of a convenience and piece of mind thing than a necessity. Being able to see her means we know if that big thud was her kicking the wall vs falling out of her crib without getting up and running into the room. We almost always keep the volume muted though, it’s a small house and we can can hear her just fine except for if we’re both outside.
The advice I give other parents is to not buy anything but the absolute basics until you really need it because a lot of things you think you’ll need you probably don’t.