The landlord has to have access to your apartment in case of repairs or emergency. I would think that if they let you change the lock it would have to meet their standards and also that they will want a key for the new lock. Better ask your landlord before changing it.

 I think it depends on your contract with the landlord. But in most cases, you can't change locks without discussing with the landlord or letting agency. You may get fine if you secrectly do this. Check with your landlord first!

 Yes you can change the locks on your door. You have to make sure the landlord knows it and is giving a spare key in case of emergencies. Just save the old lock and put it in a box for when you move out so you can put it back on when you choose to move in case the landlord doesn't like the new style

 I have always heard that you can not change the locks without consent because you do not own the property. Most landlords will not have a problem with you doing it, but need prior notice and need to give the owner a spare.

 NO! Definitely NOT! A renter is not allowed to make ANY changes to a rental property without permission from the landlord-written permission!