The number of steps of backup to ask for depends entirely on where the horse is in its training and what purpose the backup is serving in the session. For a horse just learning the exercise, one or two steps done softly and correctly is worth more than ten steps done with resistance, head-raising, and bracing. The quality of each step is more important than the quantity of steps, and drilling backup steps on a horse that is still bracing its neck and dragging its feet teaches the horse that bad-quality backup is acceptable.
Building backup steps starts from one. Once one step is reliably soft and prompt, ask for two before releasing. Once two steps are reliable, ask for three. The progression from one step to ten steps typically takes several sessions spread over several days, with each session confirming the previous standard before adding to it. A horse that will back ten soft, straight, engaged steps from a feather-light cue is a horse that has had its backup developed methodically over time — it does not happen in a single long drilling session.
The rule about ending on a good note is particularly important with backup work. If you are asking for eight steps and on one particular repetition the horse backs eight steps beautifully — softly, straight, from a light cue — that is the moment to stop the backup exercise entirely and do something else. The horse that gets released after its best effort learns to offer its best effort. The horse that is kept backing after a good repetition learns that good effort doesn't produce release.
For practical purposes, a horse that will back ten to fifteen straight, soft steps from a light halter cue has all the backup it needs for any real-world situation. Backing more steps than this is useful for specific performance requirements like reining patterns, but for general horsemanship the quality and responsiveness of the backup matters far more than its length.
