Selection of needles and threads is essential for obtaining high-quality stitch. When fabric, needle, and threads mismatch, the stitch will be uneven, some stitches may be missed, processed material may shrink. Therefore, needles with large diameter and thicker threads are used for sewing thick materials, while thin needles and threads are preferred for thin materials.

Depending on diameter, the needle is marked with a number, e.g. No. 80 = 0,8 mm -  with two decimal places of millimeter; or 8,10,12 in - in inch fractions. Thus, the larger needle number is the thicker it is. If the package has 2 figures (e.g. 80/12 or 90/14) then the needle size is specified both in millimeters and inches. Modern sewing needles vary not only by core diameter, but by tip sharpening versions, eye form, groove sizes, etc. All these parameters that we may consider as insignificant and unapparent influence the stitch.

Thus, the needles vary by field of application - type of material they are meant to be used with.

Sewing threads varying by fabric composition, structure, and manufacture method are applied for manufacture of clothes. The following values serve for classifying the product range of sewing threads: thread purpose, composition, finishing, and structural properties, such as quantity of additions, direction of final twisting, linear area (thickness).

By purpose value, sewing threads are divided into threads for clothes, footwear, embroidery, surgical threads, threads for darning, etc.

By finishing value, sewing threads are divided into grey, matte, glossy, white, black, colour threads. Today many sewing thread are manufactured with special finishing, including fire-resistant one. 

By composition, sewing threads are divided into natural, chemical, and combined (made of chemical and natural components).