The barefoot hoof acts as an indicator as to the overall health of your horse, e.g. when the hooves do a lot of work before they are ready the horse will get footsore. Being footsore is not in itself harmful to the horse but it forces the horse to slow down and so to look after itself. Footiness is a sign that something is not quite right. It may be too much grass, too much grain or an ailment such as thrush or an abscess.
As the health of the horse’s hoof improves you can exercise more. The more exercise your horse can do at a comfortable level, the more robust and healthy your horse’s hooves will be and the better they will perform. If you proceed at the pace of the hoof, it will get tougher and stronger year by year. So take it easy to start with and build up the exercise gradually. I can advise you of an appropriate level of exercise for the stage of your horse's rehabilitation.
In the wild horses can travel up to 25 miles a day. Unfortunately most domestic horses do not travel this distance in a week! Exercise speeds up the metabolism of the horse which increases the rate of hoof growth thus reducing the rehabilitation period.
If you address your horse’s diet and environment before taking their shoes off this will assist in the time taken to rehabilitate your horse from shod to barefoot.
If you need to work your horse on surfaces which they are not yet comfortable on, you may need to consider using boots on your horse for some of the time to begin with, especially if your horse has thin soles or is metabolically challenged as you will need to maintain an exercise regime in order to build a better hoof. I find that even a horse with thin soles can cope well without boots on a smooth tarmac surface which will help to build sole.
If things are not progressing well do not be tempted to shoe until the problem has been fully diagnosed. To shoe without a diagnosis is simply masking the problem rather than solving it.