Needles and heads solve different problems
Needles are thread positions on one embroidery head. Heads are separate sewing stations that can stitch multiple pieces at once.
When six needles can be enough
If most designs use a small color palette and manual rethreading is rare, a six-needle class may cover the workflow. Field size, caps and service can matter more than unused needle bars.
Why ten needles is a practical middle
Ten positions can cover many corporate logos and recurring palettes while leaving spare slots for common colors. It can reduce operator interruptions without automatically increasing machine footprint as much as larger commercial systems.
Why fifteen or sixteen needles helps production shops
More positions allow recurring house colors and specialty threads to stay loaded and make complex multi-color work easier. The benefit is reduced color-management labor, not fifteen-times output.
Do not buy needle count in isolation
Verify maximum field, cap driver, free-arm geometry, support, training, actual run speed and maintenance access.