mRNAs move to cytoplasm where they go through translation. mRNA is not meant to store information for the long term. After processing is complete and protein is synthesized, mRNA used in translation is degraded by exonucleases that shorten the poly-A tail. When the tail is short enough, degradation enzymes break it apart into reusable parts, which are retained in the cell to be reused, and unusable parts, which are eliminated from the cell.