Thread tension is directly influenced by the bobbin casing of a sewing machine. It secures the bobbin in place, allowing the machine to unwind the thread without injuring the bobbin winding mechanism. With the right tension, bobbin thread may be used to create consistent and balanced stitches. A bobbin is a need if you want to sew anything useful. That's why every sewing machine needs a bobbin case.
To ensure that the bobbin casing wears evenly, it is desirable to replace the complete thing. Now that they're so widely accessible at such low prices, it's a lot simpler than it was before.