Studying for an hour every day" is unattainable.
"I will study English for an hour every day" is an unattainable task. I will study English for an hour every day this year" is a task to be completed on New Year's Eve, which is a little too far from the goal. As the term "three-day monk" suggests, human beings are not good at continuity, so it is doubtful if they can continue for 10 days. First of all, we need to measure how much we can do.
Supplementary explanation of why "studying English for an hour every day" is an unachievable task. No matter how many days you do this task, you will still be in a state of "I have to study tomorrow".
No matter how many days I try, Tasks not completed. On the other hand, if you fail even for one day, you cannot recover. If you limit the time period to "this year," it becomes an achievable task because it can be completed if you do it every day until New Year's Eve.
But no matter how hard I try, it will take 365 days to accomplish, and I doubt very much that I will stay motivated during that time.
The closer you get to the goal, the better. The shorter the time period, the closer the goal.
Do it every day for a month, every day for a week, every day for three days."
There is another way to look at it if the period is reduced to one day.
When you say, "I will study one hour every day for n days," when do those n days begin?
Often, don't we unintentionally make it "tomorrow"?
If you want to achieve the goal of "studying for an hour every day for one day," it is faster to do it for an hour now than it is to do it for an hour tomorrow.
To think about doing an hour tomorrow without doing an hour now is mere procrastination. ---
This page is auto-translated from /nishio/「毎日1時間勉強する」は達成不能. If you looks something interesting but the auto-translated English is not good enough to understand it, feel free to let me know at @nishio_en. I'm very happy to spread my thought to non-Japanese readers.