Do not say, "I will study Torah when I will have free time," because you may never have free time (Ethics of the Fathers 2:5).
When we have a certain task before us, the lazy bone in ourselves (and we all know it well) has two ways of thwarting our good intentions - outright refusal and delay. Since outright refusal will likely arouse the resistance of our conscience, we sometimes do an "end run" and achieve the same goal with procrastination. People who have destructive addictions - whether alcohol, drugs, or food - are notorious for saying that they will quit "tomorrow." They may say so with utmost sincerity, but laziness does not affect good intentions, only constructive action.
Furthermore, procrastination feeds upon itself, for it not only delays constructive action, it actually makes that action more difficult. As the deadline approaches, we have less time to do it right.
That which should be done, should be done now. Myriad reasons will invariably come to mind. "I cannot learn now. My mind is tired from an exhausting day. I will be able to understand and retain what I learn better when I arise early in the morning." These "reasons" are generally nothing but excuses for laziness.