What it tends to be about
Taurus is the sign of what lasts: money, land, the body, routine. Saturn there asks whether your security is real or just familiar, and what you'd keep if you had to choose.
People in this return often describe questions about worth. What am I holding onto because it's mine rather than because it's good? What would I build if I weren't afraid of losing what I have?
Why it lasts years, not days
Saturn takes about 29 years to circle the zodiac and moves slowly enough to cross the same degree up to three times as it goes retrograde and direct again. Your exact passes depend on the degree Saturn held on the day you were born, which is why two people born a year apart get different dates.