Salvation is Never Earned or Achieved
We are saved in a moment when we believe on Jesus Christ for salvation. Period.
See this post for more: Salvation
But can believers at any point in this present life become sinless? Absolutely not! Many Pentecostal false churches teach this outlandish heresy.
1 John 1:10
If we say that we have not sinned, we make him a liar, and his word is not in us.
As it is written, There is none righteous, no, not one.
Only Jesus ever lived a perfect life.
What about after we are saved?
Do we need good works to "maintain" our salvation or somehow keep it from being "lost" as if that were possible? No! The bible is very clear on this.
This only would I learn of you, Received ye the Spirit by the works of the law, or by the hearing of faith?
Are ye so foolish? having begun in the Spirit, are ye now made perfect by the flesh?
Looking unto Jesus the author and finisher of our faith; who for the joy that was set before him endured the cross, despising the shame, and is set down at the right hand of the throne of God.
Our salvation rests entirely in the finished work of Jesus Christ. We cannot "lose" our salvation and it is not up to us to "maintain" it. A believer is sealed by the Holy Spirit and cannot be unsealed.
Do we need works to get to Heaven?
The bible answers this clearly as well. Works are for rewards and blessing other people but have nothing to do with salvation.
But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
Not of works, lest any man should boast.
What happens if you get to Heaven but have no works?
The bible answers this as well.
1 Corinthians 3:11-15
For other foundation can no man lay than that is laid, which is Jesus Christ.
Now if any man build upon this foundation gold, silver, precious stones, wood, hay, stubble;
Every man's work shall be made manifest: for the day shall declare it, because it shall be revealed by fire; and the fire shall try every man's work of what sort it is.
If any man's work abide which he hath built thereupon, he shall receive a reward.
If any man's work shall be burned, he shall suffer loss: but he himself shall be saved; yet so as by fire.
See my notes on this important chapter here: 1 Corinthians 3
Can I combine grace and works to get to heaven?
Nope. It is one or the other. If you are seeking to justify yourself and attempting to gain entrance into Heaven by what you do or don't do, you will be very disappointed when that day comes and Jesus says He never knew you.
And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then it is no more grace: otherwise work is no more work.