The pictured plants do not appear to be declining due to Boxwood Blight, primarily because we don't see any characteristic excessive defoliation nor dark lesions on the foliage. You can use the information in the linked page (as well as our boxwood diagnostic page) to examine the stems and foliage more closely to confirm whether diagnostic symptoms are present, or share close-up photos here if you would like our interpretation.

Boxwoods are vulnerable to a variety of pest and disease problems, plus environmental stresses (like drought and over-mulching) that make them more susceptible to those pests/diseases. These symptoms resemble Volutella Blight damage, especially since it's a very common infection that follows plant injury or stress. Boxwood Leafminer is also a very common insect pest of boxwoods and there may be indications of their feeding damage as well (it's hard to tell at this distance). Neither of these issues kill a boxwood (at least, not unless it suffers from repeated heavy infections/infestations), but they can weaken it and hamper recovery. Volutella kills branches but does not kill the main root system, so damaged plants can be drastically cut back so they can regrow evenly. Given how slowly boxwoods grow, though, a recovery to their former size would take several years, at which point replacement might be more practical instead.

If Boxwood Blight is present, its spores can remain infectious on the soil surface for about six years. Replanting, even with more disease-resistant boxwood cultivars, is not recommended unless you select a shrub species that is not susceptible. Fortunately, only boxwoods and their relatives (Sweetbox - Sarcococca, and Pachysandra) contract this particular disease. While you don't have to try sterilizing the soil (which wouldn't be practical or possible anyway), try to select replacement plants that should be suited to the conditions present in that planting site, rather than trying to alter aspects of the site conditions to suit particular plants. In other words, if an overhead gutter overflows or that nearby roof downspout leaks extra water into the root zone of what's planted there, look for shrubs tolerant of temporary wetness. Similarly, if the soil there is not very acidic due to leaching from the home foundation or nearby paving (which only a laboratory soil test can determine), an acid-loving species like holly would not fare well long-term and might be more prone to root rot from the stress. (Japanese Hollies, for example, look nearly identical to boxwood with their small, spineless leaves, and are sometimes grown as an alternative for that appeal.)

If Boxwood Blight is not present or suspected and you prefer to replace the plants instead of waiting to see if they recover after pruning, you can replant with new boxwood if you select the most disease-resistant cultivar(s) available as added insurance against future infection. When growing boxwood, avoid trimming the shrubs into dense, manicured shapes (despite their tolerance of it and the popularity of the practice) because this creates a thin layer of very dense outer foliage which is more likely to be infected; that light-blocking layer also encourages leaf shed from the interior so that little to no foliage remains on the branch bases if trimming needs to remove dieback or reduce the plant's size. There are dozens of boxwood varieties, some of which mature quite small on their own, and usually with a rounded growth habit without intervention. No boxwood variety is immune to problems, and using a fungicide will not cure an existing infection, but preventative measures like cultivar selection and letting more airflow reach the foliage by limiting pruning can help them fare well on their own. When mulching, use a relatively thin layer of only about an inch of mulch since boxwood roots are sensitive to oxygen soil levels that are reduced when using too much mulch or landscape fabric.

We checked our records and noticed that we received a similar question last October from a similar email address, which we will link to. If this was your submission, we're sorry you did not receive it; perhaps the response got lost in a spam folder or system glitch from Ask Extension.

Miri

Thank you for your insight and information. I’m attaching two pictures closer to the plants that you might be able to help me. I was the person who asked the question last October. I feel like I’m losing time since it’s going into spring and need to figure out what I should plant. I very much appreciate your knowledge and the work that you do. Thank you, Lynda

Good morning Lynda.
We can't see any detail in your photo that suggests Boxwood Blight is your problem. 
As Miri shared, these plants can have many issues, particularly when stressed (like us they are more prone to illness or decline when they are stressed).
Site or care conditions that are not ideal often cause decline over time, such as when they are sheared into little meatball shapes (when sunlight is able to reach the center of the plant they naturally would/should have leaves all along each stem) or when they are mulched too deeply (only an inch is recommended but we can see from where the drainage goes into the mulch that it must be more like 3" to cover that black downspout connecter pipe). 
If you can improve conditions you could cut out dead areas and try to let them come back but they are very slow growing and won't look great for quite a while.
If you want to replace them, we'd suggest using different plant material, including native plants if possible. Do you need to have that tight, English Garden look? Does it need to be evergreen? Would you be o.k. with a more natural look that might offer  blooming color or fragrance?
We'd need to know how much sun the area gets and how wet the soil tends to be to make suggestions, but some possibilities could include native Yaupon Holly, a native Boxwood look-alike Inkberry Holly, or Osmanthus. You would want to look for cultivars that match your site conditions and desired size. 
There are good plant nurseries in Howard County, including one that specializes in native plants. 'Gem Box' or 'Strongbox' Ilex glabra are new and look very much like boxwood. We don't personally have experience with it but the specialty nursery could guide you.
You don't need to feel too rushed- April- May are still good times for planting (and some nurseries may not be fully stocked yet).
You have time to get a soil test done: 
https://extension.umd.edu/resource/soil-testing-and-soil-testing-labs/

Here is our watering information, which is critical. Even if someone else plants for you, monitoring for watering needs (and knowing how to best do it) are crucial for the first 18-24 months of establishment for best success:
https://extension.umd.edu/resource/watering-trees-and-shrubs/

If you are using a company for mulching, no more than 2-3 inches (and one for shallow-rooted boxwood) should be used over plant/tree roots and it should be kept pulled back from contact with bark/stems/trunks.


Christine

You are welcome. We're always happy to help.
Enjoy your weekend too. These days I tend to think "March showers bring April flowers!"