Upon moving into your new home you should throw a party so all your friends can know where you now live before anything can get broken. You may also get to meet your new neighbours if it's too rowdy so keep it respectful and save that bit for later when you'll probably be able to present a better picture of yourself.
Then change your locks. Many people, 60 per cent by some counts, don't and so they have no idea who else has keys to their home. They don't know if spares are hidden somewhere, if the previous folk could find all their old keys to hand over or if the odd forgotten builder still has a set. Perhaps the neighbours you woke up at 3am have a set because they used to feed Tiddles and water the plants while their previous, quiet, neighbours were on holiday.
At least you know that all estate and letting agents operate along scrupulous moral guidelines and never hand out keys to people who want to get into a property on their books. They never leave them in drawers, on hooks or in glove boxes and they never lose them. They also never have the address on a label. (These all happen.)