Why do I see the same kanji again?

You see the same kanji again because the review system uses spaced repetition to strengthen long-term memory. Items are shown multiple times at increasing intervals, especially if they are new or if you had difficulty recalling them.

Repeating kanji may feel redundant, but it is essential for moving knowledge from short-term memory into lasting recognition. Once you consistently answer correctly, the intervals become longer and the kanji will appear less often.