There isn't a driver in any 43-car field who doesn't have at least a little something to prove. But here are the five who'll have the most judgmental eyes on them going into Daytona.
It's not his fault that there has been nearly two years of buildup to his arrival at Hendrick Motorsports, but now Kahne bears the burden of proof not only that he belongs there but also that all the hoopla was justified.
Team owner Rick Hendrick looked before he leaped when Kahne became available early in 2010, then couldn't get Mark Martin to retire and had to farm out Kahne to the tenuous (and now gone) Red Bull Racing for '11.
The media coverage just kept on -- e.g., would crew chief Kenny Francis move to Red Bull and thence to Hendrick with Kahne? And then, yes, he would, and did.
Some fans seem to have gotten so sick of it that now they're asking whether we haven't overrated Kahne. Well, the guy won six races for Ray Evernham in '06, so a better question may be whether Hendrick will deliver the equipment Kahne deserves with the 5 team.
On the other side, face-to-face conversations with NASCAR fans lead me to believe that the driver best known for his female and youth followings has a quiet but very significant fan base among adult males. They're anxious for him to prove he's a top-tier driver who'll produce results they can brag about.
Even Kurt Busch haters are skeptical that the Dinger can fully replace him at Penske Racing, and Allmendinger acknowledges that "I've got big shoes to fill."
Dinger Doubters can't get past his winlessness in Cup after four seasons, or ever forgive his early awkwardness in full-bodied cars after moving over from open wheel. But if they could, they'd see that he learned to get to the front and just couldn't stay there with the mediocre cars provided him by Richard Petty Motorsports.
That's what Roger Penske and lead driver Brad Keselowski saw in Allmendinger when they signed him during the winter. Now his task is to get back up front again, but this time to "close these races," as he puts it.
That should happen. Keselowski seems willing to work closely with his junior teammate who's actually 2 years older at 30. The good news about Penske being the only major Dodge team in Cup is that all of Chrysler Corp.'s race-engineering resources go there.
Still, when the yellow No. 22 goes up front, the Dinger Doubters may think two things in rapid succession: First, "That's Kurt." Then "No, that's Allmendinger. And we've seen him up front before."
With every lap he leads, Allmendinger now must prove he can lead the next one.
Not since he arrived as a rookie in 2001 -- and was jostled on the pit road by Dale Earnhardt before the start of the Daytona 500, then slammed and flipped off by Earnhardt early in the race -- has the elder Busch brother had more to prove.
And he hadn't even left a trail of tantrums back then.
So can the onetime prodigy who was handed a great ride with Jack Roush (and blew it) and stepped into a very good ride with Penske (and blew it) go back and start over with shoestring Phoenix Racing? And keep his temper consistently on the way back up?
He has something to prove from the ground up, starting with old-guard team owner James Finch, who knows what winning tastes like. Remember, Keselowski won Talladega for Finch in 2009.
Busch arrives vastly more heralded than Keselowski did, so getting at least one dark-horse win this season is almost obligatory. And another one or two wouldn't hurt, if Busch wants to keep his stock up among the elite teams.
Her mountain is higher even than what is obvious. She needs a win, or at least to run up front some, more than any other driver in NASCAR, to ease both sides of the Danica Debate.
Incremental progress, race to race, has grown unacceptable to detractors. And it has become agonizingly unfulfilling to her believers.
She needs more nation-dazzling runs à la her first outing in a stock car, in the ARCA race at Daytona in 2010, when she threatened to win before finishing sixth in the draft.
Aggressiveness is what she must prove this season in her full Nationwide and partial Cup schedules. To do that, she needs to get comfortable when her car is sideways. And to get there, she needs to listen to everything the veteran drivers -- nearly all of whom are pulling for her for the good of NASCAR -- tell her.
An insider with mentor Tony Stewart tells me that my notion, that she needs lots of time on a dirt track, has been talked about. But a time must be found the day after a major race has been run at Stewart's Eldora Speedway to ensure the track surface is properly conditioned.
When Bobby Rahal brought her to the Indy 500 in 2005, he said, "What we can't have is another Anna Kournikova" -- referring to the attractive Russian tennis player who became more of a model and spokeswoman than a competitor.
To shed that yoke, Patrick must prove something to herself: that sliding cars around is not a bad thing in NASCAR.
I know, I know: This guy was potty-trained on a hot seat. So what's new?
Well, it's the immediacy of a chance for a jump start: a win in the Feb. 26 Daytona 500.
We've seen that race both bolster and shatter his rhythm for ensuing seasons.
He's still among the four or five best restrictor-plate racers in Cup, but needs to reaffirm that -- to himself more than anybody else.
Now may be prime time for that. He was the most outspoken driver against tandem racing, and now, if NASCAR's tech efforts come to fruition, that will have been resolved in time for the 500.
Junior's forte always has been maneuvering in, and indeed leading, big drafting packs.
And yet, putting him back in his comfort zone gives him yet something else to prove.
Ed Hinton is a senior writer for ESPN.com. He can be reached at firstname.lastname@example.org.