The value of keeping baseball cards really depends on a variety of factors related to the specific cards in your collection. Most baseball cards have little intrinsic value beyond sentimental worth. There are some key considerations that can make certain cards financially valuable to hold onto long-term:

One of the primary factors influencing a card’s value is its condition and grade. Only cards that are in near perfect, mint condition hold significant value to serious collectors. Any creases, flaws, imperfections or signs of wear decrease a card’s condition grade and therefore its value exponentially. Also important is whether the card has been professionally graded by authentication companies like PSA or BGS. An officially slabbed high grade card sells for far more than even a flawless raw card. So proper long-term storage and protection methods are key for cards to retain optimum value.

Next is the specific player, team, season and status of the print run. Iconic legendary players from earlier eras like Babe Ruth, Joe DiMaggio, Hank Aaron naturally hold the highest values, as older cards are extremely rare surviving specimens from over 50+ years ago. Raul Ibanez rookie cards for example have essentially no collectible worth outside of personal nostalgia. Rookie cards or special subsets like rookie debuts of modern greats like Mike Trout, Bryce Harper or Juan Soto that were printed in low numbers have proven to gain value rapidly as their careers progress.

Whether the card is part of a iconic set also impacts value. Complete sets of vintage 1950s and 1960s Topps, 1959 Fleer and especially unopened wax packs and boxes from the early years are virtually collector’s items on their own. Even common low-numbered cards can gain value simply by being part of sets known for their historic value to the hobby. More recent ultra-premium sets like Topps Chrome, Bowman’s Best and Topps Archives have proven gains while bulk commons fade.

The supply and demand forces of scarcity and new collector interest also create value spikes over time. Older cards that were once considered commons later gain traction as generations of collectors discover players they are nostalgic for. Card shows, auctions and online marketplaces raise awareness of condition scarce gems and serially numbered parallel and autograph cards, fueling demand among completionists. This demand spike can ignite a card’s initial value in an exponentially growing market.

Lastly comes the integrity and stability of the collecting industry itself. As long as baseball cards and memorabilia maintain a strong cultural connection among fans and financial underpinning through enthusiastic collector spending, then the overall market conditions remain primed to support cards as long-term investments and appreciable assets. Downturns or saturation in the collecting market have historically led to short-term softening, though values rebound as markets regulate.

So in summary – while the vast majority of common cards hold little intrinsic worth over time, a small percentage that meet criteria including condition, player/set pedigree, scarcity and cultural cachet have the potential to gain significant financial value if held long-term as investments. But proper storage care is mandatory, and market fluctuations are still a factor outside individual card quality. If condition is unknown or a large varied collection was assembled for fun over worth, cards still hold lasting nostalgic enjoyment beyond strict fiscal analysis as well.