Breaking your lease may seem like the easiest way out of an apartment you can no longer afford, but it's important to remember that it could do some major damage to your credit scores too.
Breaking the lease itself isn't what will actually hurt your scores. However, by "walking away" from your lease you're breaking a contract you entered into with your landlord. If you don't pay the applicable fees or try to work with your apartment manager to find a new tenant, there's a good chance they will want to sue you to recoup their losses after you leave. This is when things can really head South.
If a judgment is acquired against you, it will show up on your credit reports and that is what will significantly damage your credit scores. In addition, judgments can often remain on your credit reports for up to 10 years and can even be renewed in some states.