Q. I have an old wooden front door with sidelights. The door is in bad shape and leaky, but the sidelights are fine. Is it possible to replace just the door and not the sidelights to save money?

Avoid the temptation to overhaul a midcentury modern home’s entire facade when remodeling or adding on. Not only is this a daunting design challenge, but it can also be prohibitively expensive.

The glass-panel door has a sidelight and windows above to bring sunshine into the high-ceiling foyer. A stone fireplace anchors a corner of the living area in the high-ceiling great room.

Q: Now that I am older, I want to replace my wood front door with a lower-maintenance one. Would an insulated, stainable fiberglass door be an attractive, efficient alternative? A: Although new ...