Personal Development is the most important thing you could possibly focus on. I personally focus on my own personal development over 5 + hours a day.
From Affirmations and meditation, to working out, to my sauna and cold plunge use. Self educating, reading new books and learning new skills.
Everyday is a new day to get better than the day before. Its a dog eat dog world out there so if you're not doing these things and keeping yourself as sharp as can be, you will be defeated. Success in life starts with your personal development.