: 2 to 3 bundles are usually enough for a full look.
: Hair with the cuticles kept intact and facing the same direction. This prevents matting and tangling.
: 3 bundles are the "magic number" for standard fullness.
: Curly or deep wave hair appears fuller, so you might need fewer bundles compared to straight hair. 3. Match Texture and Color Weaves 101: Everything You Need to Know About ... - Unruly
: 4 or more bundles are needed because longer bundles have less "weft" density.