|Your brain can be your friend.|
You may have read somewhere that it takes some certain magic number of days to form a habit; Twenty-one is the most popular. However, that is closer to the minimum number of days. According to the latest studies, it takes an average of 66 days, or 18 to 254 days to develop a new habit.
The habits you strive to develop during Lent may or may not stick before Easter. That's okay, as long as you don't give up. Your brain is there to help.
However, we are not just white-knuckling our way out of bad habits and into good. By now (Bear hopes) you have planned your Tower of Lent down to the last penny. The Bear is all about Lenting smart. That means plan what you can accomplish, and accomplish what you planned. If you find that your plan isn't working, that's okay. Roll back on your haunches and figure out why.
One question to ask is whether you need to step back and discover a foundation habit before you begin to build. If, for example, you are not a person of regular habits, you may find any tower you attempt to build to have a foundation of sand.
You see, we seldom accomplish anything through sheer willpower. We must figure out specific, practical ways to avoid near occasions of sin. In other words, be smart and give yourself the best chance of success. That may mean making changes to your physical environment and daily routine; it will always mean frequent appeals to God in prayer. Unfortunately, we are seldom taught this. We are often merely exhorted to be more like this or that saint, say certain prayers, and in general, just be determined to be better.
And we wonder why we so often fail. Jesus was always using practical examples in his parables for a reason.
Sometimes we will fail. But, research shows a stumble or fall here and there does not appreciably slow the development of a new habit.
The Bear cannot tell you when your Lenten resolve to say the Divine Office, or read the Bible 30 minutes every day, or say a Rosary with your family every day (the latter two are both worth a plenary indulgence, with the usual conditions) will stick. He can't predict how long it will take to get out of a bad habit, either. He can predict that it will seem like all sorts of obstacles will rear their heads to stop and discourage you, though.
However, the research shows that if you stick with it, it will take root in your brain. And that's not even counting the help of the Holy Spirit.
We used to be told that our brain never changes, that nerve cells were the only cells in our bodies that were not renewed. We now know that's nonsense. The human brain is plastic. In other words it is like clay, and physically adapts to thoughts and experiences.
Every time you say "no" to a bad habit and say "yes" to a good one you are changing your brain a tiny bit, and a little closer to behaving like the person you want to be. (By the same token, every time you say "yes" to a bad habit, that will change your brain, too.) You may have become more like the person you want by the end of this very Lent. More likely, it will be sometime later. However, you can have confidence that, if you don't give up, you can do do it, with God's help.
Romans 12:2 (RSVCE2) - "Do not be conformed to this world, but be transformed by the renewing of your mind."