It must depend on local rules and laws. Here in BE I was always taught that it is mandatory to carry both pilot's log and the plane's log but expressly not the plane's maintenance log. Frankly, my only way to never forget registering a flight is to do so immediately after landing so I carry it all the way. One of my instructors attached great importance to registering the exact same times in pilot's log AND aeroplane log AND aerodrome log - there must have been a time when the guys in black compared them. Not clear whether they still do today.