All beginnings are difficult (Rashi, Exodus 19:5).
We are creatures of habit. Learning something new may take effort, but once we make something a part of our routine, it becomes not only effortless, but automatic. For example, when we learned to walk, it required conscious effort, as we can see when we observe children taking their first steps. Later on in life, walking takes no thought at all. The same holds true for many other behaviors. Whenever we begin something new, we are, by definition, initiating some new type of behavior. The body naturally tends to return to the old, effortless pattern. If the new behavior holds promises of significant gain (such as a new job, new business, or new learning), which we anticipate will be profitable, this anticipation of reward overcomes the resistance to change, and we make the adjustment to the new. When we see no tangible gain, such as in spiritual advancement, the ease of routine is likely to draw us back to well-established habits.
Let's face it. If we were offered a significant promotion at work which would necessitate arising half an hour earlier than usual, we would certainly set the alarm clock and get up promptly. If, however, we resolve to devote that half-hour to bettering ourselves, we would have trouble getting up.
We must value our spiritual goals so much that we will be willing to make the changes in our routine that are necessary to achieve them.