How much are you willing to donate before concluding it's more efficient to just buy a new MacBook? Even the cheapest models now are faster, more energy efficie

How much are you willing to donate before concluding it's more efficient to just buy a new MacBook? Even the cheapest models now are faster, more energy efficient and more secure. You don't have to throw the old one away if you can find a use case for running old software but I don't think there are many people running 'power user / developer' like tasks on old hardware, especially if their jobs depend on it.