I try to let them get to taxi speeds as I have found that taking over too early does not give F/O's the chance to get used to the brakes and directional control at low speeds beyond where you would stow the reversers. The Challanger 604 only has one tiller but can be twitchy under brakes so taking over too quick denies them the practice. Also we have no auto brakes so landing on wet runways means that you could compromise landing distance by transitioning braking control, so I just lets them stay on them, antiskid clicking away getting the practice in.