Start with the three measurements: width, depth and height. Map the footprint on your bedroom floor before buying, including walking space around the bed and lid swing clearance if the box will sit against a wall.
Height matters more than people expect. A box that is too tall can feel bulky at the foot of a bed; one that is too low may not store much and can look lost. Most blanket boxes sit between 45 cm and 55 cm high, which is usually a comfortable height for reaching in or perching on.
Check the lid design and hinge function. A lid that stays open on its own is safer and more convenient, especially if children use the room. For end-of-bed use, measure the bed width, walking space and lid clearance before buying.
Look at the finish, material description and weight limit. Solid wood, MDF with wood veneer, painted finishes and fabric-topped ottomans all behave differently. If you plan to use the box as a seat, check the stated weight capacity and whether the lid is padded or hard.