Mitt Romney is in the process of finding out, as the general election campaign begins to take shape.
Right now it's hard to see how the exhaustive, bitter, financially draining Republican contest helped the presumptive GOP nominee in any way.
He endured a numbing 20 debates and struggled to eke out delegates while fall opponent President Barack Obama drew no Democratic challengers and enjoyed a mostly free ride until now.
And some of the woes confronting Romney, including the gaping GOP disadvantage among women voters, are largely not of his making.
That gap was widened by earlier divisive comments on issues important to women mostly by other Republicans, especially the debate over access to contraception fanned by Rick Santorum's rhetoric.
But the grueling primaries also may have taught Team Romney to think and act quicker, as it did this week when the "war on women" reached the boiling point when an outside Democratic consultant remarked that Ann Romney "never worked a day in her life."
The Romney campaign sprang into action. The candidate's wife opened a Twitter account and defended her decision to stay home and raise five sons as "hard work." Soon she had 12,000 Twitter followers.
The campaign churned out "Moms Drive the Economy" bumper stickers. And Obama ended up disavowing the consultant's remarks, saying "there's no tougher job than being a mom."
Obama himself likely honed his campaigning skills from Hillary Clinton's hard-charging 2008 challenge. On the other hand, determined primary foes weakened President Jimmy Carter in 1980 and President George H.W. Bush in 1992. Both lost the presidency.
The final fallout for Romney won't be known for some time.
Follow Tom Raum on Twitter: http://www.twitter.com/tomraum . For more AP political coverage, look for the 2012 Presidential Race in AP Mobile's Big Stories section. Also follow https://twitter.com/APCampaign and AP journalists covering the campaign: https://twitter.com/AP/ap-campaign-2012 .