A lot depends on the band in question. If a band is competing at the elite level (or aspires to that level), standardization allows chanter and drone sound to be as uniform as possible. The higher pitches go (and they've been climbing over the last 30 years or so), the harder it can be for a pipe section to blow a consistent, uniform tone. It would be next to impossible to expect 18 pipers to stay in tune if each were using different reeds/chanters, especially on a very hot or very wet day.

Some less competitive bands don't have the money, experience, or desire to get all of their pipers playing the same equipment. So while bands like Simon Fraser Univ. might be standardized almost to ties of their drone cords, its not unusual to see pipers in parade bands playing a wide array of different reeds and chanters - often what came with their first set of pipes. Not a bad thing, just makes it much harder to get everybody sounding the same.

As an instructor and a band player, I can say without any hesitation that bands that match reeds, bags, and chanters (I think SFU went so far as to go matching drones - but that could be wrong) make a huuuge difference when it comes to the overall sound quality of a pipe band and the time it takes to tune. Not only does the equipment help, but when a band commits itself to that level of professionalism, they become that much more dedicated to playing well.