I have a tall cactus in a window with a few tiny little babies at the bottom of the plant. The tall plant is leaning AWAY from the sun. Should I rotate the plant and if so, how often?

1/4 turn per week is usually recommended. Somehow I doubt sun-avoidance is the cause of the lean, however.

I rotate my cacti 1/2 turn every week or two. If the plant is leaning toward the light, you can aim the lean away from the sun and it will self-correct. If the plant is leaning just because it likes to lean, the orientation will make no difference.

Your cactus might need to be repositioned slightly in its pot to make it vertical.