You’re probably used to it by now, but did you use to have trouble talking about past habits in English?
Part of the problem is that “use” used to be an intransitive verb meaning “to be in the habit or custom.”
Well, “used to” and “still is,” because we still use it that way — but exclusively in the past tense. I would sound insane if, for instance, I said “Still using to eat eggs every day, I’m concerned about my cholesterol.” On the other hand, no one would blink twice if I said, “I used to eat only egg whites, but it turns out the yolk was on me.” They wouldn’t laugh either.
So, why would I ever use “use to,” you may be asking yourself? Because of the verb “do,” most frequently with questions. For example, “Didn’t you use to like going to the beach?” Normally, to answer such a construction I’d drop the main verb and repeat the helping verb — i.e., “No, I didn’t” or “Yes, I did.” But, for the sake of argument I could reply, “No, I never used to,” or, “Yeah, I used to until that lawsuit established my birthday suit did not constitute a bathing suit.”
Truth be told, this isn’t an issue in spoken English. “Used to” and “use to” sound identical because the “d” and “t” in “used to” blend into a single consonant sound. Here’s an article on Merriam-Webster about it.
And here’s noted grammarian Mitch Hedberg on the subject: