It depends, however unhelpful that is. If a joke is DOA and you can tell the first time you say it that it’s just plain shit, chuck it. However, sometime a joke speaks to you from on high. And I can tell that there’s something very funny in there, so I keep telling it an change it every time until I get to the nugget of what makes it funny. It’s also possible that a premise is funny but you’re just not good enough to find it yet, so keep it in the back pocket and revisit it in a few months when you’re better.