When ham has spoiled it will have a bad smell that will likely make you want to vomit.
The spoiled ham may also be slimy in feeling and the flesh of the ham will usually begin getting dull and also change from it's current color to a grey color.
You'll usually know for sure just by smell alone that the ham has spoiled and should be thrown out.
Ham should keep in the refrigerator for up to 4 days before it spoils and goes bad but if you put the ham in the freezer you can keep the ham in the freezer for 6 months to a year.
When you get ready to cook the ham and it smells bad or looks bad then it's best to throw it out and avoid getting sick from the food.