I seem to hear 准备 and 预备 used for “prepare” and not as often to mean “plan". 我们准备搬到美国; emphasizing the need for specific preparations for the move. Myself, I use 计划 or 打算 for planning something. 我们打算看新的电影; emphasis on merely being a future plan。 What are the differences in usage between 准备 and 预备? At what point can one not use these to mean ”plan“?