Keeping security deposit when tenant breaks a lease

[Chris Heeren]

I just had a tenant tell me today that they are breaking their 1 yr lease and will be out of the house this weekend.  I'm thankful that I won't have an eviction but was wondering if anyone out there keeps the security deposit if they break the lease or if this is even legal. It will most likely go until the first of next month until it will get rented out which is an entire month without rent.  Any thoughts?