This a big question for anyone who has or wants to have a performance horse. There is endless discussion about what makes good hooves; foot balance, nutrition, genetics, environment - the list goes on.
In "Feet first" we tried to give practical advice based on what we knew was effective for most horses but at the same time we are constantly learning new twists and refining our practices.
Equally, horses being horses, there will always be exceptions who break the rules and need different solutions. Its something I talked about recently in http://rockleyfarm.blogspot.com/2009/10/dont-lose-sight-of-horse.html
All this means that if you want to assess whether hoofcare is a success for a particular horse, you have to look at the outcome, not the process.
If your horse is capable of a high level of performance, week after week and season after season, and if their level of performance is improving rather than deteriorating, then that horse's hoofcare is a success - simple as that.
Conversely of course, if thats not happening, then maybe something needs to change...