It's generally better to keep all of your clubs the same flex to maintain consistency and performance. Mixing ladies clubs with stiffer or heavier shafts can make your swing feel inconsistent and reduce accuracy.

Not at all, the same way that some men may benefit to the lighter shafts ladies flex provide, faster swinging ladies will benefit more from using a men's senior/regular or stiff flex shaft. It's all to do with swing speed, not gender.

The main difference between ladies and senior flex shafts is the stiffness, weight and length. Ladies flex shafts are generally shorter in length, lighter in weight and not as stiff as senior flex shafts are. This helps golfers with slower swing speeds generate more clubhead speed and launch the ball higher. Both are designed to help improve distance and consistency, but ladies are the softer option.

Yes some men can use ladies flex shafts if they are shorter and swing is slower as this will suit ladies flex shafts. Some juniors will also use ladies flex when they are between junior and regular flex golf clubs.