Pruning Leafy Shrubs
Have you ever noticed how, over time, shrubs become scrappy looking and misshapen ? Unfortunately, in our culture, pretty much zero info on proper pruning is passed along from parents or introduced in school (unlike other countries).
In the USA it is typical for crews or homeowners to approach an overgrown shrub w/ electric shears and gradually create a shape like an upside down goats cheese container where the leaves on the upper portions shade out the leaves on the lower parts. When this happens the poor shrub gets leggy and scrappy on the bottom and instead of nearby shrubs growing into a graceful shape what you end up with is a polkadot efect of ugly individual bushes.
For the sake of the health of the plant and for the sake of beauty you want your pruning to leave the lower branches extending out further than your upper branches so they get some full sun as it passes overhead. Even if your goal is a tightly trimmed geometric hedge you want to consider a slight outward angle on your vertical sides. You typically see this in England where they know a thing or two about gardening.