If you'll study on — or practice a regulated profession with — a foreign degree, start its official recognition early (homologación or equivalencia via the Ministry's Valida-TE portal); these files move slowly

Spain distinguishes between recognizing WHAT you studied (equivalencia) and licensing you to practice a regulated profession (homologación). Either way the file moves through the Ministry's Valida-TE portal, and either way it's famously slow — start it the moment Spain becomes a plan, not once you arrive. If your profession is regulated (medicine, law, engineering, teaching…), don't sign anything that assumes you can practice before the recognition lands.