Not as much as you think - the people selling them want you to think the old ones were awful and need replacing, but they were designed for both reasonable efficiency and decades-long life. (You really need to factor in a literal 6-10x lifespan difference into efficiency and environmental impact figures, too...)
I have a large 60s/70s vintage chest freezer I bought on Craigslist a few years ago. I worried that it was power-hungry, so I got a Kill-A-Watt and monitored it. I don't remember the exact figures I came up with, but it was pretty negligible: Even in my non air conditioned (but attached) garage in Austin (with the highest electric rates in the state, by far), it costs me only about a dollar a month to run. So we're saving a ton of money by being able to buy and store as much frozen food as we want, at a cost of $45 up front to buy the freezer, plus a buck a month to run it - that's a deal to me.
All appliances, back when they were made here in the USA, lasted for decades. I have a cousin who had a (admitttedly expensive at the time) KitchenAid dishwasher from circa 1960! (In very cool copper color!) It still ran perfectly when she sold her ranch house several years ago.
I have a large 60s/70s vintage chest freezer I bought on Craigslist a few years ago. I worried that it was power-hungry, so I got a Kill-A-Watt and monitored it. I don't remember the exact figures I came up with, but it was pretty negligible: Even in my non air conditioned (but attached) garage in Austin (with the highest electric rates in the state, by far), it costs me only about a dollar a month to run. So we're saving a ton of money by being able to buy and store as much frozen food as we want, at a cost of $45 up front to buy the freezer, plus a buck a month to run it - that's a deal to me.
All appliances, back when they were made here in the USA, lasted for decades. I have a cousin who had a (admitttedly expensive at the time) KitchenAid dishwasher from circa 1960! (In very cool copper color!) It still ran perfectly when she sold her ranch house several years ago.