Use a second sheet.
Score book question

Use a second sheet.
Ok thanks, that's what I was thinking. Do you just write cont... or something at the top of the new sheet?

write on the back. in the lower right corner of the front, just draw an arrow pointing to the right...since it isn't really pointing to anything, it will imply that the page should be turned and then the reader will see the game's continuation.

I had that situation once, where a game lasted 103 moves, and my scorebook only acommodated 80 moves per game; I simply went to the next page, and wrote "cont." in game number box.

Well, writing down moves is not always required, but if you do happen to exeed 80 moves, it is almost essential to write down moves if time allows it, simply because, if it does go past 80 moves, there are more chances for three move repetition and 50-move rules to be called, and they can only be proved or disproved if either person has a scoresheet to show what happened.
I have never went to a chess tournamnet before, and have a question about score books. What happens if the move count exceeds the score sheet's limit?
I have a 80 moves per sheet book. So I don't think I will incounter this often. But I wanted to know, just in case.