We use "used to" to talk about things that happened in the past, but don't happen any more:

I used to ride my bike to work.

But if you want to talk about things that didn't happen in the past, there are a few different ways to do it. One way is "used to not ___":

I used to not like broccoli when I was a kid.

To talk about something that you had many chances to do, which you always chose not to do, you can say "never used to ___":

I never used to sleep in late, but in the last couple of years I've started to sleep in until ten or eleven on weekends.