A security deposit is that which you pay upfront in the event that there are any damages or negligence committed towards a rental unit. This is a way for the Landlord to protect their property. With that being said most people expect to receive their deposits back when their lease is up and they move out, but that isn’t always the case.

“I didn’t cause any serious damage to the apartment, why didn’t I get my security deposit back?”
You don’t have to cause any serious damage to the apartment to not get your deposit back. Answer these questions to make sure you have done all you can to make sure the apartment is as close to it was when you first moved in:
Did you follow the rental agreement?
Your landlord can charge you for making minor alterations to the property if this was something that was forbidden in the terms of the lease. Just because you see a paint job as an upgrade doesn’t mean your landlord does. Negligence can be a lease-breaking charge as well. This could include not properly cleaning the house or not maintaining the plumbing, heating or air conditioning fixtures.
Did you cause any minor damage?
By this we mean creating holes after nailing shelves or pictures on the walls. Check to see if any hooks, doorknobs or anything else of that nature needs to be tightened. It’s that little extra step that goes a long way.
Did you thoroughly clean?
This means all the places and spots that most commonly get looked over – the op of shelves & cabinets, in crevasses etc. Give the apartment an extra boost of cleanliness before it’s time to move-out.
Now, do you think you will receive your security deposit back? Put yourself in your landlord’s shoes. They need to protect their property and their business. Doing that extra bit of work and inspecting the whole place, down to the hooks on the wall, not only helps you to collect that deposit money back but shows respect.