It seems to me that a plant will reach what I consider an optimum size. Unfortunately, I have not developed a way of freezing time in order to maintain that perfection. Bonsai probably comes the closest to this, with pruning another option. However, sometimes plants seem to suddenly get too large to the point where you can no longer bring them back to the size you liked them best.
An example of this is a series of six Castewallen Gold conifers that we planted in September 1990. We even spaced them out widely, but they were fairly fast-growing, and reached what I considered a perfect size by the middle of 1993, a moment to be frozen, at least in a photograph, forever.