Let’s say you decide to go all-in on Spanish. You quit your job, fly off to Guatemala and enroll in an intensive 4-week Spanish course. You study for 5 hours a day until your brain turns into mush. You come home having nearly reached the conversationally fluent level.
But then what happens?
You settle back into normal life, you all of a sudden have other commitments, there are fewer opportunities to practice, and your Spanish starts to regress. This is an example of high intensity, low consistency learning.
When you can’t maintain a high level of intensity, you’ll forget what you learned very quickly, because your memory follows a decay curve and it needs to be reinforced regularly. That’s why after cramming for a college exam, most students feel like they’ve forgotten everything after just a few days.
On the other end of the spectrum, there are people who have been learning Spanish for years. They spend 5-10 minutes a day with a free language app, and then maybe once every few weeks they go to a Spanish meetup in their city. They’ve doing this for 3-4 years and are barely conversational.
This is an example of low intensity, high consistency learning. Since the intensity is low, it’s not difficult to keep that up week after week. However, progress is extremely slow and sometimes this can cause people to give up altogether.

Like many things, there is a nice middle ground that you can shoot for. In my opinion that “sweet spot” is about 1 hour per day of learning time.
Most of us lead busy lives with work, school, family and social obligations taking up much of our time. Yet we should try to learn Spanish with a moderate level of intensity, because few people have the patience to wait 4 years or more to learn a language.
If you can dedicate more than 1 hour a day, then that’s fantastic, but the more time you spend, the more difficult it will be to maintain that pace consistently.
If this sounds like too much of a commitment to you, then ask yourself, are you busy for the sake of being busy? Most people waste a lot more time than they realize, and occupy themselves with “activities” that keep them busy but don’t accomplish what’s truly important to them. Freeing up an hour a day isn’t as hard as you think.