Good or bad to rearrange cage?

So I was thinking about rearranging some of the things in Hannah's cage. FN cage by the way. However, I didn't know if this was beneficial or not. Is it good to keep them stimulated by moving ledges etc or can they hurt themselves? Sometimes she runs laps like crazy in the middle of the night and with it being dark I don't want her to fall or knock herself silly by being confused. Just wondering :). Thanks.