I guess I am old-school because I do NOT trust the wear bar method when it comes to MC tires. I rely on a good visual inspection of the whole tire, the actual depth of the tread, actual mileage on the tire itself, and the date of the tire's manufacture. Also....Riding double will result in quicker wear of the tires and brake pads and does factor into my decision to replace all as needed.
I don't take any chances when it comes to tires or brake pads....I replace them all early and as often as needed....We have enough road hazards to deal with and I don't want/need to worry about tires/brakes when I am out there on a ride.
Lastly....Pay attention to the air pressure in your tires!
Boomer....who sez when ya have pygmies along for the ride ya need to be extra cautious....