The question to ask ourselves is 'am I hungry for God's Word? NOT am I a disciplined person.
Memorize to KNOW GOD, to think on God to commune with God.
Don't memorize to be able to say I have memorized the book of Revelation.
Is my heart, mind and soul tethered to the Word of God?
Memorizing scripture is NEVER unproductive time. It is an oasis for the mind and soul.
Seven times a days I praise you for your righteous rule.
This is an example of constant reflection on God's character. It is not suggesting an exact number but a continual turning to God's Word throughout the day.