Spanish letting laws are indeed different from those of the Uk. Shorthold tenancy agreements are normally done for periods of one week to a few months, and the way of ensuring that the tenant does not decide to extend the period -in Spain, all tenants have an optional right to extend the tenancy agreement to up to 5 years, being ths right of the tenant a manadatory extension for the landlord- is by agreeing on a high rental sum. This will deter tenants from enforcing the tenant friendly laws currently in force in Spain.
If the tenants does not pay he can be evicted by the Courts. Where the tenant damages the property or furniture, he can also be sued. However, there is a deposit, equivalent to one month´s rent, which the landlord keeps in order to ensure that the property is handed over in good conditions.
