Most clothing today is mass-producing, and conforms to standard sizing, based on body measurements that are intended to fit the greatest proportion of the population. However, while “standard” sizing is generally a useful guideline, it is little more than that, because there is no industry standard that is “both widely accepted and strictly adhered to in all markets”.
Home sewers often work from patterns purchased from companies such as Simplicity, Butterick, McCall’s, Vogue, and many others. Such patterns are typically printed on large pieces of tissue paper; a sewer may simply cut out the required pattern pieces for use but may choose to transfer the pattern onto a thicker paper if vast use is desired. A sewer may choose to alter a pattern to make it more accurately fit the intended wearer. Patterns may be changed to increase or decrease length; to add or remove fullness; to adjust the position of the waistline, shoulder line, or any other seam, or a variety of other adjustments. Volume can be added with elements such as pleats, or reduced with the use of darts. Before work is started on the final garment, test garments may be made, sometimes referred to as muslins.