it takes (some) getting used to

It takes time to become familiar with or habituated to someone or something, perhaps due to their unpleasant nature. I know it takes getting used to the boss's unpredictable nature. I love being in England, but it takes some getting used to driving on the other side of the road! Is she getting used to her new job?

It takes (some) getting used to.

It is very unpleasant at first, but after a time it will not be so bothersome. (Said in recognition of the unpleasantness of something.) I never ate raw oysters before. It takes some getting used to. These hot Mexican dishes seem impossible at first. They take some getting used to, I agree. But it's worth it.

it takes getting used to

One needs to become accustomed to something. For example, We've always had a small car, so driving a big van like this-well, it takes getting used to . This idiom employs used to in the sense of "accustomed to," a usage dating from the first half of the 1500s.