Which barbering service requires the use of a straight razor?

The service that requires the use of a straight razor is shaving and outlining. This technique is specifically designed for creating clean and precise lines, particularly when shaping facial hair or necklines. Straight razors are traditionally favored for their ability to provide a close shave and deliver sharp, defined edges, making them a popular choice among barbers when performing these services.

In contrast, trimming, layer cutting, and texturizing typically involve the use of scissors or clippers rather than a straight razor. Trimming primarily focuses on shortening hair while maintaining its overall shape, layer cutting involves cutting hair at varying lengths to create texture and volume, and texturizing is done to remove bulk without significantly changing the hair's length. Therefore, the use of a straight razor is uniquely suited to the specific needs of shaving and outlining.