I'm no expert, but I'll tell what I did with the neglected boxwood hedge and stand-alones that came with my house when I moved in five years ago.

The first job was cleaning out about 10 years' worth of dead leaves that so completely clogged the bushes, top to bottom, that literally no light or air could get through. Just getting some air circulating and letting light in went a long way toward rejuvenation. I think the poor things had been suffocating for years! (Among the treasures I found buried in the hedge were silverware and a toy fire truck at least 18" long that had apparently been missing for years!)

Next job was to do some cutting back. I did this in the spring, and continue to do it in the spring, mostly out of habit but also because I fear stimulating new green growth in the fall that will get zapped by freezes and snow.

The 'cutting back' is actually done by hand, literally snapping off 4-6" branches all over the hedge by hand to give it some shape. (I have a neighbor who lives and breathes boxwood who threatens to faint dead away if I ever go near mine with a pair of clippers. I guess if I want to kill him off, I'll wave a pair of secateurs in his face and head for my bushes!)

I try to make the upper half of each shrub a little narrower than the bottom so that the bottom gets light. (It's tempting to do the opposite, to keep the top fuller than the bottom, but it's healthier the other way.) By doing so, you help to avoid having the bottom and interior of the shrubs basically die off for lack of light and air. This is a time-consuming, but in some ways pleasantly-mindless job. I only do it really thoroughly every other spring, however; the years in between I settle for a little bit of shaping, just snapping off the really straggly long branches.

I prefer a more 'natural' shape to the hedge, which the snapping-by-hand encourages, if only because you get too tired to even consider trying to make a 'perfect' shape!

Every spring, on the heels of the shaping, I spread well-aged chicken manure under the whole 50' long hedge. Warning: even though it is well-aged, the odor can be a little ferocious until rain or watering dilutes it. Chicken manure is apparently just the yummy level of acidity that boxwood thrive on. I buy a couple of bags at my local Southern States ag supply store.

I also make a point after really heavy snowfalls to go out and GENTLY, with a broom, knock a lot of the snow off the branches, especially if I can see that they're really drooping under the weight of the snow.

If you're tackling a big hedge, or just really overgrown boxwood, you might want to divide the job up a little so you don't feel overwhelmed. Cut it back a certain amount this year; feed it; see how it improves. Then cut it back more the following year, to the shape and size you really want.

My two cents'! Others will probably have more experience and expertise to offer.

Good luck!

Thanks for the tips. My old boxwoods will enjoy the extra attention and I'll prune in Spring.