Q.I can’t trim my boxwoods too deep
I have two large boxwoods. I would like to reduce the size down to half but when I trim too deep, I run into dry stems. Does this mean that my boxwoods are spent? Should they be replaced? They have gotten to wide for the area and are impeding walkways. I’ve had these since I bought the house in 2004. They have doubled in size since then. I appreciate any recommendations.

Regular pruning of Boxwoods makes for healthy plants.
I would avoid pruning the plants in the fall as they will not have time to recover and harden off before frost.
Instead wait until early spring to trim the plants back. Try to remove only 1/3 of the plant in the first pruning. Then go back in summer and remove another 1/3.
Remove any dead or diseased plant material anytime.
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/trimming-boxwood-bushes.htm