Disclosed herein is a method and system for controlling base station buffering of data. In an example method, the base station serves a wireless communication device (WCD) over an air interface, where the air interface encompasses a quantity of channels on which the base station serves the WCD, where the base station is configured to buffer, in a data buffer, data awaiting transmission to the WCD, where the buffer has a fullness-threshold defining a maximum quantity of data that the base station will buffer for the WCD, and where the base station is configured to respond to the quantity of data in the buffer meeting the fullness-threshold by increasing the quantity of channels. Then, while serving the WCD, the base station determines an extent to which the WCD provides connectivity between at least one other device and the base station, and sets and applies the fullness-threshold based on the extent.