What happens if a tenant signs a lease, pays 1st month & dep then wants to back out after 5 days (LA rent controlled)? Deposit?

Dear landlord,

If you have a year lease, you can keep the money until you find a tenant to lease the apartment. You have to return the money that you cannot recoup by renting the apartment to someone else. For instance, if you rent the apartment after one day, you have to return all but six days worth of rent to the tenant who backed out. If you rent it out after one month, you can use the money you collected for advertising and for the month of rent you lost.