Color change isn’t always a good indicator - exposed ham and bologna will pale/turn grey in a relatively short time just from light. Instead, rely more on smell/texture. If it smells bad/rancid or is slimy, it’s best to toss it. Most cold cut meats will last between 3-5 days in your fridge, but can last longer or shorter depending on the quality of the meat and how cold your fridge is. Salami and pepperoni often last up to two weeks. Soft or semi-soft cheeses should be consumed within a week of being opened - and sooner is better for processed cheeses. Hard cheeses (no processed cheddars and Italians like parmesan and Romano) do last longer, though, and it’s often enough to trim away any moldy bits.