The definition of grace is something that really messed me up during my time as a Mormon. There is a lot of cognitive dissonance and doublespeak related to defining the terms and outlining how Christ's love is delivered.
The condition of grace, as outlined in 2 Nephi 25:23, is that you're still expected to try your hardest in everything in order to qualify for the gift. Yet without grace, we would not be able to meet God's standards of perfection.
Have you heard the parable of the bicycle? A modern day allegory thought up by Steven Robinson in his book Believing Christ where he spends over 200 pages trying to lead you through the gordian knot of the Mormon conception of grace.
"A young girl wants to buy her own bike. Her father suggests that if she works and saves her money, they will go buy a bike. The two eventually go to the store, and the girl discovers that she does not have enough funds to buy the bike on her own. Her father then agrees to make up the difference."
My experience with grace in the LDS church was to take it seriously when they say no unclean thing may enter the house of the Lord. That grace is merely a tool that enables repentance, which is a continuous process that starts with identifying sin committed, praying and working to make amends, getting spiritual confirmation from God that you have labored and struggled sufficiently, then ending with taking the sacrament on each Sunday to symbolically baptize yourself again. And that's for minor sins, like being rude one time, having a dirty thought, cursing, borrowing something without asking, etc. More serious sins you have to include your Bishop in the process in which case, when you get spiritual confirmation from God that you've struggled with the spirit sufficiently, you have to get confirmation from your Bishop that yes, indeed, you have met the required amount of sorrow and humility over the sin in order to be considered forgiven.
The idea of LDS repentance says that it is a transformative process, that it is not enough to say you're sorry and move on. It is meant to be a change in your character and your life. Yet they acknowledge that our earth life will always be plagued by sin. You won't escape your unconscious desire to sin until you die, when your spirit is separated from the natural man inherent in your body of flesh. So, for someone who serves Christ in your word and deed, who tries his hardest to live as He lived, you still fall short of worthiness continuously because of your flawed nature making you do little things that are impure or naughty or distempered. This results in someone who is otherwise a good person, a disciple of Christ who serves his fellow man with love and humility, feeling guilty and shamed and unclean all the time.
And exhausted. I was plagued by a constant Sisyphus task of being vigilant over myself and being sorrowful over falling for small temptations. Because once you find that the big sins no longer hold any weight or temptation for you, it has to be the small ones you must purge continuously. Line upon line, right? It was exhausting knowing that I could always do more.