You can keep leftovers for about 4 days in the refrigerator or for a month or so in the freezer. To reheat it, only reheat as much as you’re going to serve. About 15 minutes in the oven at 325 degrees F will warm it back up nicely without drying it out. As a rule of thumb, give smoked sweet onion honey glazed ham leftovers about 10 minutes per pound when warming it back up. Of course you can also have leftover ham chilled, in a sandwich perhaps.