1. The state generally has more resources to retain evidence than citizens; if the state is allowed to prosecute crimes far in the past, they can target defendants who cannot provide evidence in their defense due to lost records. This asymmetry can be unjust, especially for crimes of lesser impact.

2. Most people draw a line where it seems needlessly cruel to prosecute an old crime; an extreme example, should a middle-aged person with decades of good behavior live in fear of being prosecuted for a relatively small crime committed as a teenager? Conversely, if a person commits a crime as a teenager, shouldn't they have clemency if they stop committing crimes for a long time and become a good citizen? Most people prefer the outcome that people can put smaller mistakes behind them; they may debate where to draw the lines, of course.