We all have our bad habits.
Some worse than other but regardless it is unnecessary and should be overcome.
I overcame one of mine which was nail biting. Now don't get this confused with nail chewing. I bite my nails to trim them since I felt I could do it faster and more convenient with my teeth than with clippers. I did not chew them till they were nubs. Also I am not left handed so it was irritating when I had to which hands to trim.
How I over came it? I'm not sure. I just realized my nails were very long and that they should be trimmed but I didn't have the urge to bite them. Instead I waited till I got home, pulled out my nail file and went to town on them. They are now smaller, clean with a blunt end. Supposedly the nails are supposed to be square at the ends for males.
The only thing I am getting used to is typing with nails since I usually bite them to be smaller. I don't know how women do it with their long nails.
