3. Federal Criminal Appeals Are Generally Slow. If immediate results are your thing, you will probably be frustrated by the federal criminal appellate experience. Generally, federal criminal appeals take many months, if not a year or more. Why? The federal courts are crowded, and the process of an appeal is, by its nature, slow. The courts, for the most part, consider each case and each legal claim individually, which takes time. Technology has helped speed up parts of the process in recent years.