Deviating from the Schedule; the Solution?

It's usually not a good sign when one's working by lamplight instead
of daylight by the time they get to work on the most important
item on the To-Do List . . .

    Schedules are great! They put the events of a day in order, they keep a person from forgetting important tasks, and good schedules ensure that there's enough time to get everything done that needs to be done.
    But when one has this fantastic schedule that gives just enough time to get all the work done, and one ends up not getting to anything on time because they chose to deviate from the plan . . . everything on the schedule gets shifted time-wise, and it's definitely not great. Things that are supposed to be done around evening-time can become a late-night task, or something to quickly attempt to finish in the morning. Not getting to work at the right time also crams up the day even more, taking from minutes of "breathers" that could have been had the schedule not been altered.
    On top of those things, not doing something scheduled when it's scheduled to be done devours time, it's succumbing to distractions (not the small things like sharpening a pencil, but larger jobs like sharpening every pencil one has), and when one finds themselves scrambling around to finish the important stuff at the last minute, stress and guilt usually join forces to make a person feel really, really crummy (and tired).
    It's yet another form of procrastination, along with a few other things. Hesitation for fear of messing up the task (I think I posted about that in September), and having a sudden thought to do something else (a decidedly more interesting work than the scheduled activity) can also contribute to the frustrating and guilt-prompting choice to not get to work when one really needs to.
    So let's see; what are the solutions? Prioritizing, remembering the reasons why tasks need to be completed ASAP, remembering what happened the last time the planned schedule was shifted; all of these are good, but it seems sometimes that they can be easily forgotten when one's caught up in an unplanned task.
    So maybe involving other people would strengthen these solutions. Requesting that a friend ask about the progress of something major on the To-Do List, asking a family member to point it out when they notice you surfing the Web for a while. It's hard to forget the importance of a task when someone else is talking about it, right? What do you think?