Syracuse and its older suburbs are full of well-built homes from the early and mid 1900s. They have good bones, but a remodel almost always turns up something the original builders never planned for.
Plaster and lath walls are the most common. They are solid, but they crack, and they are heavy and dusty to remove. Depending on the room, it can make more sense to take them down to the studs or to cover them with new drywall. Both are reasonable; the choice affects cost and schedule.
Plumbing and wiring are next. Galvanized steel supply lines corrode from the inside, and older wiring was not designed for modern kitchens full of appliances. When the walls are already open, it is the cheapest time you will ever have to replace them.
The practical takeaway is to hold back a contingency of 10 to 15 percent on any older-home remodel, and to work with a contractor who prices changes in writing before doing them. That way, what is found behind the walls is a decision, not a surprise on the final invoice.