It is always advisable to place your Spanish property or any other asset here in a Spanish will. This will ensure that the matter can be dealt with expediently in the event of your death. Your Lawyer will advise the best way of doing this and it can be included in the overall costs in connection with your purchase. He will also advise of any potential tax liability for the inheritor of your assets. An English Will can have your Spanish assets included in it but the procedure for proving it here in Spain can be extremely drawn out. A simple word of advice would be: never leave your assets to the state, leave it to who you wish via a Will.