The Monday following the Conference Championships is almost always the most expensive day to buy.
If the stress of not having a ticket will ruin your pre-game experience, "pulling the trigger" when you find a price you're comfortable with is the best strategy.
If you require a specific section (like the 50-yard line) or a large block of seats together, buy as soon as you find them. Last-minute inventory is usually scattered and limited to "nosebleed" sections.
Sellers often drop prices sharply in the final 24 hours to avoid being left with "worthless" paper once the game starts.
Historically, prices can drop by 25% to 40% on game day compared to their peak two weeks prior. Historical Price Trends: Peak vs. Kickoff
Historically, ticket prices follow a predictable downward trend starting from the moment the matchup is set until kickoff.