I think newborns sleep extremely heavily in general, even to the point where they'll just sleep in full daylight in a room full of people because I guess they just need that much sleep. But after a few months they settle into whatever their actual level of sleep-heaviness is going to be; in our case it's pretty middle of the road - she doesn't really get disturbed by noise from another room provided it isn't excessive, but would probably stir if one of us went into her room and started making noise moving things around
Related question - we're looking ahead to Christmas and considering visiting family, but my parents place is a little cramped for us + the baby, and we are worried about her sleeping badly and disturbing everyone. So thinking about booking a place to stay instead, but what is the best thing to do there? Most hotel rooms are just the 1 room + bathroom, so feel like if we put her down to bed we'd then have to walk on eggshells and likely would still struggle not to keep waking her up. What do people do? AirBNB maybe that would give us more than one room?