I'd argue if you find yourself needing to do this, it actually might be a hint that abstracting is appropriate, as it's proof there is more than superficial com

I'd argue if you find yourself needing to do this, it actually might be a hint that abstracting is appropriate, as it's proof there is more than superficial commonality. Like so many things, I don't think there's a way to make any hard and fast rules, and figuring this out is more art/experience/taste than science. Not including cross-cutting concerns that modify all usages (eg, changing your logging or dependency injection library).