In or into.........?

Question

when do you use the word "in" instead of "into"?

what's the difference between them?

Answer 1

"into" implies a continuing action, like "I was walking into the store."

"in" implies that the state of being inside the thing is a constant, like "I was in the store for several hours"

Answer 2

In is a part of the present tense.  Into is a part of the progressive tenses and the periphrastic future.

Simply: you are in the living room and you can go into the kitchen if you want.  One of them is static and the other is a part of an action.

I'm gonna get into sports when I get old enough.  (periphrastic future)

I'm into sports (ongoing action, present progressive)

I'm getting into the shower. (present progressive)

In is used for location and other static descriptions.  I am in the car.  She is in the band. (present tense)

Hope that wasn't too confusing.