During my career as a horticulturist, I once worked as a landscaper. One of my duties was to prune trees, shrubs and perennials. We had demanding clientele that took pride in their pristine landscapes.
I remember being terrified of cutting a huge hole into a shrub or cutting a plant too short. My boss use to always tell me that “you can cut more off but you cannot glue it back on.” These were words to prune by.