In this case, it is not primarily the age of the manuscript that matters, but our ability to trace particular readings to types of texts with strong and ancient pedigrees. Some later mss. The geographical distribution of a reading is significant, though often difficult to discern for beginning readers. The text-type of a manuscript source can be significant. Witnesses are weighed rather than counted.
Readings supported by both Alexandrian and Western witnesses are usually superior.
Often the Alexandrian text alone will provide the most probable reading. Most manuscripts belong to the Koine or Byzantine type. It is also very ancient. The Caesarean text-type shares common features with the texts used by Origen while he was in Caesarea. Its readings are quite diverse in their affinities with other text-types.