In the afterlife nobody needs tzedakah; it’s too late to give charity. “Today is the time to do them” (Avodah Zarah 4b).Not tomorrow. When a man understands the purpose of life, life becomes very important. There’s no such thing as “spare time.” He’ll never want to “kill time.” Life is not monotonous. Every moment is an opportunity. If you say even one line of Tehillim or think one thought of emunah or have a thought of appreciation for your fellow man; if you love and appreciate your spouse, your parents; if you appreciate the freedom of a country where you can walk in the streets without being arrested by the secret police; if you are happy that there are jobs, that there are things to buy, that the sun rises and sets, that there is morning and night — you are utilizing your life. You are truly living. People who don’t appreciate these things are wasting their lives. Use life to thank Hashem and sing to Him, to improve yourselves, your middos, your character, your mind. Fill your mind with Torah thoughts and teachings. That’s shaping your soul. By doing so, you are preparing your personality that will someday be restored to you, not only in the World to Come but at Techiyas Hameisim, when we are once more joined with our bodies and understand how great the achievement was in spending our lives performing acts of virtue.
Astor, Yaakov. Rav Avigdor Miller on Olam Haba (p. 143). The Judaica Press, Inc.. Kindle Edition.