Fitted sheets have elastic edges for several practical reasons:

1. Secure Fit on the Mattress The primary reason for the elastic edges is to ensure that the sheet stays securely in place on the mattress. The elastic helps the sheet grip the corners and sides of the mattress, preventing it from slipping or bunching up, even if you move around a lot while sleeping.
2. Ease of Use Elastic edges make it easier to put the sheet on the mattress. Unlike flat sheets, which require tucking luxury fetted sheets in all around the mattress, fitted sheets with elastic can simply be stretched over the mattress corners. This makes the process quicker and more convenient.
3. Neat Appearance A fitted sheet with elastic edges gives the bed a neat and tidy appearance. The sheet lies flat and smooth across the mattress, with no loose fabric hanging off the sides, which contributes to a well-made, aesthetically pleasing bed.
4. Accommodation of Various Mattress Sizes Elastic edges allow fitted sheets to accommodate slight variations in mattress size and thickness. Whether your mattress is a standard size or a bit thicker due to a pillow-top or mattress topper, the elastic allows the sheet to stretch and fit snugly.
5. Comfort Since fitted sheets stay in place, they help prevent discomfort caused by sheets that bunch up or shift during the night. A smooth, secure sheet enhances sleeping comfort.
6. Durability of the Fit The elastic creates a more durable fit over time. Without elastic, sheets would need to be tucked in continuously, leading to more wear and tear on both the sheet and mattress over time. Elastic helps distribute tension more evenly, reducing this wear. In summary, the elastic edges of fitted sheets are designed to keep the sheet securely in place, simplify bed-making, ensure a smooth and neat appearance, accommodate different mattress sizes, and enhance sleeping comfort.