Echoes again in Porter Square as two businesses renovate, but the sound is confusing — suggesting either waste and folly or an admirable sense of completism. The businesses: the Qdoba Mexican Grill replacing the McDonald’s in the heart of the square; and the Bread & Butter minimart replacing a White Hen Pantry on its outskirts. Both have gutted the interiors of their predecessors and are rebuilding almost from scratch.

For Qdoba, a step up from McDonald’s in atmosphere, this makes some sense, although it was startling to see the kitchen demolished recently along with the cold plastic dining area. But for Bread & Butter … well, it will be worthwhile to visit when it opens just to assess how significantly the work changes the minimart experience.

There are plenty of places where real estate is more valuable than the property on it, and that could be what’s in play at Qdoba, where the kitchen was undoubtedly designed so specifically on a McDonald’s model that the evisceration — if not exenteration! — is required. But at the Bread & Butter, what’s taking shape inside looks disturbingly familiar.

If it’s worth tearing down completely, is it worth rebuilding exactly?