The residence permit implicit in non-lucrative residency lasts for a period of 1 year initially, renewable for a period of 2 years. Note that you may only be absent from Spain, i.e. live outside Spanish territory, for a maximum period of 180 days under the non-lucrative residency programme. Once you have been resident for 3 years, you can renew one more time for a period of 2 further years, at which point, having lived in Spain for 5 years, you can apply for a permanent residence permit.