Although I had heard this advice often enough, I never believed it was all that important, until something happened to change my mind recently.
For just over 6 years, I worked from home full-time as a freelance writer. I'd noticed that I was struggling with procrastination more and more, and that my productivity had steadily declined over the years; but although I was constantly trying this or that method of improving my time management, I never instituted a daily schedule.
Then, just two months ago, I started working a part-time job in the afternoons: My productivity (and my client base) had declined enough that, if I wanted to continue my rather expensive hobbies (horses and collecting dolls) unchecked, I would have to find another source of income, so I took a job as an after-school nanny.
I was resolved to continue to maintain my same clients and workload as before, however, which I knew meant I had to get everything done in much less time. Impossible, right? Yet somehow, knowing I had a time limit energized me to get things done that I wasn't doing in twice the time before. When I had unlimited time, I was more prone to goofing off and not doing my work during the day; but knowing I had less time, I was more likely to get right to work, despite distractions and my tendency to procrastinate.
Now I understand what all those helpful bloggers and work-at-homers meant when they said to set a daily schedule. Having a set amount of time to do something, rather than feeling like you have all day, can definitely help to curb procrastination and limit how susceptible you are to distractions!