Yes. You have to practice self-denial every day so long as you live. The day you say "I did enough" is the day your soul perishes.
No. Nobody has to practice self-anything to get into heaven.
And your soul does not perish when you say *I did enough*. Your soul was already perished.
As long as *I* is in it at all, you will not be saved.
It's JESUS did it for me.
No, self-denial not is the way of salvation, death to self is. When we die in Christ, we are raised with Him, and it's nothing we do to earn it or deserve it as it's by grace, without effort on our part.