General Pruning Thoughts
In time garden shrubs often need pruning to improve their value. They may be overgrown and not blooming as well, they may be crowding their neighbors or the walkway, or they may just be misshapen and fugly. Research seems to show that when a shrub needs major surgery it is best done in that sweet spot after the nights are not brutally cold and before the shrub leafs out for spring. The energy stored in the roots can then be used to produce lots of beautiful new growth. If your shrub is a spring bloomer your shrub will put out lots of nice new growth but that season's blooms will be lost. There may be cases where your shrub is so overgrown that the spring blooms fail to satisfy, in those cases I would consider hacking away. If your shrub only needs shaping a pruning after flowering has ended would be better and may trigger a second bloom.
Evergreens are also pruned on a schedule according to type, Portland Nursery has a very helpful breakdown on evergreen pruning advice.
I have a dwarf Euonymus alatus and a pink Spirea that were planted nearly 20 years ago. I probably should have spaced them a little further apart, the Euonymus is invading the Spirea's personal space and causing it to grow crooked. I had considered trying to relocate the Spirea which is less than 2 feet tall. I think instead I will prune them both back to about 6 inches at the end of March. In addition I will try to remember to layer the Spirea by nicking a low hanging branch and pinning it into the ground. I understand Spireas are easy to root from cuttings but layering can be done at any time and is more forgiving to us forgetful types. At about the same time I plan to see how far back I can whack my neglected boxwoods. In the meantime I am taking advantage of this bundled up weather to remove my neighbor's floribunda roses. They have grown to about the size of a chicken coop with trunks about an inch in diameter. This is not entirely altruistic, I will be very glad to see them gone.