When buying a Spanish property for holidays or living less than 183 days a year, you will be considered a non-resident. As a non-resident owner of a Spanish villa, you will have to:
Appoint a fiscal representative in Spain.
Make a Spanish Income tax declaration and pay tax on any income you will earn in Spain.
Pay local rates.
Make a declaration of all your capital assets in Spain and pay wealth tax on them if necessary.
Pay utility bills (direct debits through your bank may be the best idea).
If you buy property in Spain because you want to live there permanently, you are a resident and you will have to:
Apply for work permit or permits to open a business.
Import your car, furniture moving, etc.
If you are retired, you should discuss with your bank the easiest way to transfer your pension to Spain.