This topic has been covered many times in these blogs. Summary answer: Depends on which state you invest. I like TX because of the 25% in 6 months premium I get for fronting the $$ needed by the local municipality. You don’t have to be a resident of the state in which you buy tax liens. No need to spend big bucks to learn the process. States like CA hold Tax Sales after 5 years of trying to get the property owner to pay up. A lien is just that. A sale is just that. Learn the difference.