Answer:
As the age of an object gets older, the half-life of the probe needed to accurately estimate its age should get relatively longer. This is because the longer the half-life of the probe, the more time it has to decay, and therefore the more accurately it can measure the age of the object. For example, if an object is very old and has very little of the original isotope remaining, a probe with a shorter half-life might not have enough time to decay and give a accurate measurement of the object's age. On the other hand, a probe with a longer half-life would have more time to decay and give a more accurate measurement.