if you pay your first last and deposit when you start rent then when it comes to the last month of rent that you pay nornally when you give in your notice can they use the last month as extra deposit
The deposit is either to hold the property or to cover any damages you might incur. First and last should be for the first and last month of the rental
If you mean, can you ask the landlord to use the deposit amount ( usually on months rent) instead of paying the last month's rent, then the answer is no because the landlord does not have access to those funds as they are in a deposit scheme. The landlord can only access the deposit or part of it if they successfully claim damages to the rental home.