The Cardinals have added guard Mike Iupati (center) and tackle Jared Veldheer (right) in free agency to protect Carson Palmer.

There are conflicting schools of thought when it comes to NFL free agency.

Many see it as fool's gold, citing the long list of players who signed lucrative contracts and then went bust. Others see it as an ideal way to supplement a roster, filling critical needs with players who have proven NFL ability.

The truth, like most things, is somewhere in between.

Yes, the Packers and Patriots are two of the most perennially successful franchises in the NFL, and both are notoriously averse to free agent spending sprees. But they also feature the two best quarterbacks in football, and any strategy that starts with Aaron Rodgers or Tom Brady behind center seems likely to work out.

The 49ers similarly tend to ignore the free-agent market, but that plan didn't help them remain competitive after an exodus of talent in recent years.

On the flip side is the Denver Broncos, a team that went heavy on free agent signings a few years ago, and rode Aqib Talib, DeMarcus Ware, Emmanuel Sanders and others to a Super Bowl championship. The Giants and Raiders have also been aggressive in free agency of late and have markedly improved.

It hasn't worked out as well for the Jaguars, who have constantly made splash signings over the past several seasons but continue to wade among the NFL's cellar dwellers.

"It's obvious there's not one way to do it," Packers coach Mike McCarthy said. "If there was, people long before us would've figured that out and everybody would be doing it by now."

As free agency officially begins at 2 p.m. (AZ time) on Thursday, the most important thing for general managers is to remain calm as the chaos swirls around them. There is a lot of cap space available, and players may get offers that exceed their ability on the field.

Fans will be screaming for action, when in reality the most prudent decision may be the one that doesn't make the headlines.

"We've always been a draft, develop, keep-our-own (organization)," Steelers General Manager Kevin Colbert said. "I think you're seeing more teams doing it. And as a result, you're seeing less and less quality free agents. There's an inherent danger in that, because some of the players who are hitting the market with the number of dollars that are available, might not be quite worth what they're going to get paid because of the supply and demand."

It's a tightrope the Cardinals know well. General Manager Steve Keim would like to re-sign many of the team's starters from a season ago, but the expectation is that safety Tony Jefferson and defensive tackle Calais Campbell are going to be among the most sought-after players on the market.

Teams that have consistently won over the past few years naturally have a deep reservoir of talented players, and it's impossible to keep them all. The Seahawks felt this crunch last season, watching outside linebacker Bruce Irvin and left tackle Russell Okung depart in free agency.

"It's what the NFL is about," Seahawks GM John Schneider said. "It's about parity, and you can have all those teams that will be able to do that much more than you possibly can. So you have to move those pieces around and try to stay in the game with those free agents, and your own free agents, as much as you possibly can."

Flexibility is always key. The Cardinals went hard after pass rushers early in free agency a year ago but weren't comfortable with the asking price. Instead of compromising their beliefs, they worked out a trade for Chandler Jones, who had 11 sacks in his first year with the team.

"There are lots of ways to improve the team," Cardinals president Michael Bidwill said. "It's just not free agency and it's just not the draft. There are things that we can be doing and will be doing to be very aggressive."