I make my own because no commercially available one was just right. Its fun and easy and a great way to get started on a sewing machine. All straight seams, maybe curved corners, and a few tie-ups. I get used flat sheets at the thrift shop, cheap and you can feel the thread. More on reddit.com

I would buy a Queen size duvet cover that measures 90x90. (Some queen size comforters and duvets may vary in size.) More on reddit.com

I see no problem with that strategy, honestly. The duvet cover often is the most expensive element in many instances. For example, I always recommend a linen canvas duvet cover since it's so damn durable and breathable out of all the fabric options available but it's insanely expensive ($500+ retail). This usually leaves little budget left over for a duvet insert for most people -- even when they find great deals at a few hundred dollars less from places like Ebay --- so it is not a new concept. I tend to also highly recommend silk inserts since they're great for hot sleepers and they are pretty reliable all-around (cheap ones to expensive ones). Hell, I have a cheap all-season silk insert from Costco (SilkHaven brand) that works really well for the price I paid for it, so buying budget-friendly duvet inserts sometimes is not a bad thing at all! The more expensive silk inserts tend to be either really nice outershell options or really high-end silk grades (6A) which raises the price quite a bit (but doesn't increase the breathability of the silk fill too much, overall). Overall, though, you'll probably do pretty well with a more average-priced insert as long as the filling material you're buying is breathable and decently durable. More on reddit.com

Any dry cleaner with a sewing machine can easily cut any duvet cover down to your size More on reddit.com