When you are focusing on your expectations, having a timetable can have beneficial or harmful effects on their achievement. It all depends on how you set the timetable.
If you have a long term timetable, like what you want to accomplish in the next year, or five years, and your goals (aka expectations) are reasonable, then a timetable can actually help you to work toward them. It can keep you from slacking off, help you to continue to take action to move toward them. It can help make clear to you what you need to do to make it happen, or make certain choices more clear as certain choice that don’t necessarily prevent you from reaching your goals may still take you off the path toward them long enough to disrupt your timetable.
On the other hand, they can be harmful when you set unrealistic timetables, or set in stone shorter term paths. If your timetable absolutely requires you to get this done today, and that tomorrow, and the other thing the next day, then unforeseen circumstances can disrupt your entire timetable, bringing much stress and possibly fear of failure into your life. Setting unrealistic goals can do much the same thing. You don’t want to set goals that you have to strain with all your effort to barely reach them, you want goals that you have to work toward, but have no doubt you can accomplish.
So, if you’re setting goals and timetables, go ahead and set short term goals, even daily ones are good for you, but don’t make your timetable so tight that if you miss a single daily goal it messes up the whole path and plan.