Hmmm.. My little plans like setting targets for myself in terms of study (read 3 essays and make notes by tomorrow, have to read next 10 chapters today, have to learn that new method of multiplication) usually fall in place. Such plans concern only me and it would be a shame if I didn't pull them off, considering that I try not to make unrealistic goals.
When plans include others, like let's go to a movie or something, they usually fail because someone or the other has to bail out or fuck up or the like.
I haven't lived long enough to have made any long-term plans. So i cannot talk about those