Review on 🔌 7.4 to 4.5mm Tip Adapter Converter Cable for Dell Laptop Power Supply - Compatible with 30w 40w 45w 65w 90w 120w 135w D5g6m 0d5g6m M3800 XPS 12 13 9350 3960 15 5930 5950 Inspiron 11 13 14 15 17 3000 5000 7000 [2Pack] by Kristen Vang

I've used them with 10 year old PSUs and 1 year old PSUs and haven't had any problems with matching or over current, burning laptops or anything horrible. If it's not clear from the description, they take the larger barrel tips and shrink them down to narrower barrel tips so you can use old PSUs with newer laptops (they also make the cable about a foot longer). I would guess the only downside I see is that older power adapters may not have the power to charge large laptop batteries meaning it may take longer to charge. But it's a great way to repurpose old power supplies.