When knitting traditional Socks, one typically starts at the cuff and works down. This has the advantage of being fairly straight forward, as one needs only to Cast on as usual and knit In the round. Knitting in the direction of the toe also has the advantage of easily being able to pick up stitches and reknit the heel and/or toe as they begin to wear out. However, when creating socks this way, it is not possible to test the fitting of the sock as the work progresses.
Knitting toe-up alleviates this problem. To begin, one must create the Toe. Once the toe is created, one knits in the round, gradually increasing until the desired size is reached. The foot is then knitted, followed by gusset Increases. Next, the Heel must be created, typically by reversing a standard method such as the Dutch Heel or French Heel. Finally, the leg is knitted until the desired length is reached.