We confess that we are given a full measure of sanctifying, or saving, grace at Baptism. By our actions we may literally "fall out of grace," that is, lose our grace. Partially, drip by drip, or all at once with major bad actions. This is not because God failed, but rather our own refusal of the grace of God. This grace is restored through repentence and forgiveness and this grace is strengthened by participating in the sacraments. We will need to be "full" of grace in order to stand before the Lord's throne. (Being full of grace leaves no room for sin.)
SD
The only refusal of grace that occurs is when we decide that we do not need Jesus for salvation and we can go it alone. Sin is covered by God's grace. Grace doesn't keep score. So we aren't on a scale where Havoc is at 88%, I'm at 58%, D-fendr's at 93% and you're at 93% (notice I put the Catholics high on the scale ;) ). We're either full of grace or empty. Only two categories.