Proper pruning is essential for maximizing berry harvests from plants like currants, raspberries, and blackberries, yet many gardeners make common mistakes that lead to reduced yields and unhealthy plants. Key errors include neglecting pruning altogether, which causes bushes to age and become sparse; choosing the wrong time to prune, potentially removing fruiting wood; over-pruning or under-pruning, leading to energy depletion or overcrowding; and using dull tools that damage stems and invite disease. Understanding the specific pruning needs of different berry types, such as when to cut back summer-fruiting versus autumn-fruiting raspberries, and ensuring adequate nutrient supply alongside correct pruning techniques, are crucial for a bountiful harvest.