How long can deli meat actually last?

So I’ve read that deli meat only last for about 4 days? Is this true? I’m mostly talking about Ham and Turkey.

Usually, every Sunday I like to buy deli meat for the week so I can make sandwiches. But usually on Fridays, I’ll eat something else. Or I’ll go out for lunch. Because I’m afraid to eat deli meat past the 4 day mark. But now I feel like that’s silly and one more day really shouldn’t hurt.

How long can it actually last when refrigerated?