I think they've been recording time for a while in the Ratchet & Clank universe, because if you notice at the beginning of the first game, if you are talking time as in actual hours and such, then you've got it saying 11:05 AM Local Time Veldin, so they probably have time zones on different planets and such already, kind of like we have here on Earth, and as for months and years, after you beat the game and unlock the extras menu, or goodies menu I guess it's called, you get to see magazine covers and such and in the corners of most of them, they list a date for the magazine, kind of like it would be if I bought a copy of Playstation Magazine or something. So they would already have to be recording time before the first game even existed in that case. Also, in the first cutscene of Secret Agent Clank, you notice when they do the comparison of images of Ratchet to confirm it's him robbing the museum, the one image is of Ratchet and Clank celebrating Ratchet's birthday, and they didn't really start celebrating birthdays until around the 17th or 18th century, if I am correct on my history, and they were already recording time then, in our universe, and you can't really celebrate a birthday without an actual birth date, usually, depending on whether or not you know their actual birth date, which in this case, I'm assuming they did know, as Ratchet was an infant when his father died, but from what I gather from the Future series, Ratchet remembers some of those events from that far back, in which case, he would be able to know the date he was born. Therefore, once again, they would already have to be recording time in the Ratchet and Clank universe.