The #1 complaint from clients is that stylists take too much length off. Here's a tip, gain their confidence and trust the first time they walk in the door and you will have them for life. The key to achieving this is communication and the tip of your thumb.
When a client says they want to grow their hair out to one length, most stylists will advise that the shorter the hair is cut, the sooner it will be one length. While this is absolutely true, it pushes the limits of most clients comfort zones.
Instead, use the tip of your thumb to the knuckle as a guideline for an inch. Explain to your client that the natural average in hair growth is ½ inch a month, so if they visit you every 8 weeks and you take only an inch off, they can stabilize their length and grow their hair at the same time.
Another tip for stabilizing length is altering the interior of the cut - leave the length and weight of the perimeter and add interest with disconnection and layering on the inside. Try a professional reversible blending shear, designed to extract weight and eliminate bluntness.
Another option is to add fringe and side swept for the conservatives, because it's flattering on all face shapes and grows out easily, and bold and dramatic for the trendy.