Episode 125-Retraining older horses vs starting with a clean slate

Today I'm answering two questions about older horses. One about restarting and one about a horse that doesn't want to listen when he can't see the herd. What is the difference between training a young horse vs retraining an older horse? Are there different risks starting an older horse under saddle? When working with herd bound horses…why does it seem like they just don't want to listen? Is there a difference between a subtle cue and a clear cue?