Discolored water isnt always an indication that the plumbing is near failure. Discoloration can be from a number of sources (water supply lines, water supply line maintenance, water heater, etc.). I agree that galvanized piping doesnt have an infinite life, but I would highlight it as a possibility, along with some of the other possible scenarios mentioned above.

Also replumbing isnt always required. In Houston, local guys are reporting on success of coating pipe from the inside out. It aint cheap, but it could save money by not having to rip apart walls and such.