Don’t feel bad if you mix up use to and used to now and again—it is not an uncommon mistake. Used to is a phrase that can mean “accustomed or habituated to” or refers to something from the past that is no longer true. Use to and used to are also frequently used in English grammar as modal verb phrases.
”Use” Followed by an Infinitive
Before we get into idiomatic meanings for the phrase used to, it is worth pointing out that both use and used can correctly appear before to when to is part of the infinitive of a second verb.