What type of hinges are commonly used for 1-3/8" interior doors?

The choice of 3-1/2" x 3-1/2" hinges is appropriate for 1-3/8" interior doors because these hinges provide the necessary strength and support for the weight of standard interior doors. The dimensions of these hinges offer a good balance of size and load-bearing ability, ensuring that the door can swing smoothly without sagging over time.

Using 3-1/2" x 3-1/2" hinges aligns with industry standards for both function and aesthetics in residential settings, making them a common choice for this application. They are robust enough to handle the 1-3/8" thickness of the doors typically found in interior spaces while fitting well into the overall design of the door and frame.

Other hinge sizes or types may not provide the same level of support or could be disproportionate to the door's dimensions, possibly leading to operational issues or an unappealing appearance. Hence, 3-1/2" x 3-1/2" hinges are the best choice for ensuring durability and functionality in this context.