The way I see it, spreads are well researched by vegas for an entire week. Vegas is bound to have it pretty close. But with 2nd half bets, books have 20-30 minutes or so to come up with how good they think the 2 teams have been playing, so there's much more room for error, and subsequently profit for me.
But since I'm just getting into this, are there any tips I should know? I know that if one team is up by 2 TD's or so, the under is more likely since they have no reason to do anything but run the clock down. Is it more like that the team thats losing will beat the 2nd half spread due to their need to score often? Even if that team is the Bucs?
Main thing in my experience is that if you have 2 good teams playing eachother, each with a good defense and a good offense, but generally known more for their D, then take the over in the 2nd half. The league has rigged the rules so much in the offenses favor in recent years that in these types of games, the old fashioned defensive game you would like to watch doesn't happen, and the offenses explode in the 2nd half. This is especially true for prime time and postseason games. Think Pats/Panthers Super Bowl a few years ago.