PLEASE NOTE. I often see contributors writing that 183 days is the maximum. Thiis is wrong -To be NO RESIDENTE you can stay in Spanish territory only 182 days and that includes days of entering and leaving. Also you should validate it by filing with Hacienda each year for the previous year and pay the small tax due by 31/12 to avoid fines. This is then entered into your NEI records .You can do this with a lawyer or more cheaply with a Gestoria or John at Spanish Tax Forms Ltd who can be found on-line who will do it for you.