Not really. Sometimes you know the cost right now will be less than a few hours. The future cost of the same changes will be at least that, with a very high

Not really. Sometimes you know the cost right now will be less than a few hours. The future cost of the same changes will be at least that, with a very high liklihood (sometimes, a near certainty) of being 2-10x that. Are you really arguing that this rule of thumb leads to optimal decisions 100% of the time? Because that is clearly untrue. If you want to make the argument that allowing exceptions to the rule opens up a pandora's box that is ultimately worse than just always following the rule blindly, okay. I think I'd still disagree, but it's at least a defensible argument.