Hard pruning is a pruning technique that removes quite a lot of wood. It is also known as three-budded pruning since it involves cutting apple and pear trees back to the third bud on fruit-bearing branches and is recommended for artificially structured apple and pear trees such as cordons, espaliers and fans.
You need to take account of how vigorous the tree is before you prune it. If last year’s growth was less than 20 inches (50 cm), then it is not a particularly vigorous tree and will benefit from hard pruning. You should prune in winter when the tree is dormant and cut back to three buds on each spur bearer, a lateral branch that grows on a framework or primary branch.
If last year’s growth was more than 20 inches (50 cm), then you are dealing with a vigorous tree that will be difficult to control with hard pruning. Bend the rules of three-budded pruning and don’t cut back as hard, leaving four, five or six buds on each spur bearer.
If trees have been neglected, the spur bearers are often multiple and complicated. Don’t have any qualms about simplifying them by keeping only those closest to the framework branches.