I'd say most turbos are built to last around 200.000 kms. That said the actual lifetime of a turbo can greatly vary depending on factors, like how heavy footed you're driving, what quality of fuel and oil you're using, and whether you generally take care of engine problems as soon as they're occurring.
Anything that generates excess amount of soot can shorten the life time of a turbo dramatically, and so can shutting the car off while the turbo is still hot. That's why it's recommended to let the car idle for 30-60s before shutting it off, if you just left the highway, or generally didn't cruise around in the parking lot at low speeds and for minutes, prior to stopping.
Technically any turbo should be "rebuildable", meaning the center cartridge (containing the bearings and the flaps that are driven by the exhaust gas and that compress the air) should be replaceable. However, in rare cases, where there's some other defect (like the turbo housing is somehow cracked, because for ex. cold water was spilled or has splashed on it, while it was still glowing hot), it might not make economical sense or technically possible to repair or "rebuild" that particular unit.
What exactly is your engine code?
