You should have enough income to support your family. If your spouse or partner wants to join you in Ireland, you should have earned at least €30,000 per year in the 2 years before the application. For children, the amount you should earn is based on the weekly Working Family Payment income limits for your family size.
If one obtains a Spanish residence permit for EU family members, they have the right to live and work in Spain as if they were European citizens, as well. Moreover, this right does not just apply to the spouses of EU or Irish passport holders, but also to the civil partners, children, and parents.
If you're an Irish citizen or have an EU passport, you won't need a visa to move to Spain. This doesn't mean that you'll not have any paperwork to complete when you arrive. After arriving in Spain to live, you will need to get a Número de Identidad de Extranjeros (NIE) followed by residencia and the new TIE card.
Unless at least one parent or an Irish-born grandparent was an Irish citizen at the time of your birth, you have no automatic right to Irish citizenship on the basis of extended previous ancestry (that is, ancestors other than your parents or grandparents).
You must be married to – or in a civil partnership with – an Irish citizen for three years or more. The marriage or civil relationship must be genuine and enduring. You must be living with your spouse or civil partner on the date you apply for citizenship and on the date you are granted citizenship.
For residents of the EU, retiring in Spain is quite simple. As an EU citizen, you can live, work, or retire in Spain without a visa or residency permit. However, Non-EU citizens have to apply for a visa and a residence permit.
If you have a relative who is a citizen of the European Union, you can easily get your right to reside and work in Spain. The relatives can be your spouse or your children.