When it comes to investing in baseball cards, there are a few main factors to consider that help determine cards that have strong potential to increase in value over time. The most important things to look at are the player, the year the card was printed, the player’s performance and accolades, the card’s condition and grade, and the overall supply and demand dynamics in the baseball card marketplace.

For players, the obvious choices to consider are legends of the game who have had hall of fame careers and lasting impacts. Players like Babe Ruth, Mickey Mantle, Hank Aaron, Willie Mays, and more recent stars like Mike Trout, are always in high demand from collectors. Their rookie cards from the 1950s onwards usually hold strong value. Even stars have booming and bust periods in their post-playing careers that affect card prices. It’s ideal to invest in the biggest names when they are closer to induction or already in the baseball hall of fame.

The year the card was printed is also critical. The classic baseball card years of the 1950s saw the lowest print runs and simplest designs, making vintage cards from that era highly sought after. The 1969 Topps cards that had a memorable design are also favorites. The most coveted year is 1952, with the flagship Topps set being the pinnacle. Only around 50 mint PSA 10 graded 1952 Topps cards exist in the world. Even low-grade copies can sell for five-figures. The 1970s had taller paper stock sizes and color photos starting to emerge. The late 80s and 90s had errors, refractor parallels, and oddball sets that gained cult followings. Within each decade, the scarcer the print run and rarer the card, the better holds its value.

Of course, a player’s on-field performance heavily influences their collectability long-term. Stats leaders, MVPs, Cy Young winners, and players who win or contend for World Series titles see more demand. Authentic rookie cards of such accomplished players are generally the most investible. Parallel to this, special in-game accomplishments warrant premium card prices. For example, rare cards that feature a specific home run, perfect game, or award moment capture are fascinating to collectors.

Naturally, higher quality graded cards appreciate much more over time due to their scarcity in perfect condition decades later. Professional grading services like PSA and BGS bring transparency to a card’s condition using rigid standards. Those that score a perfect “black label” or mint PSA 10 rating will demand top dollar from the most serious investors. Low-print parallel versions in top-grades are incredibly scarce and provide amplified returns. Cards must be carefully cared for to attain such lofty grades worth a premium. Lower graded copies may not maintain value as consistently in the long run.

Marketplace supply and demand dynamics move prices up and down. Periods where player/card buzz peaked nationally see highs, while wars, recessions, and collector passion cycles trigger lows. The overall rise of population and spending power in the memorabilia field has lifted all vintage boats the past 15 years. This bull market may not last forever, so solid investments usually focus on the most historically important and conditional rare pieces. Young star rookie cards can tank if hype fades, so patience in holding is wise.

Taking all these factors into account, some specific baseball cards that are often cited as smart long term investments include:

1909 T206 Honus Wagner – The pinnacle collectible, only ~60 are known to exist. Have sold for millions. ‘Shoeless’ Joe Jackson’s T206 is also very rare and valuable, topping $2 million recently.

1952 Topps Mickey Mantle – The ‘Commerce’ design classic rookie, numbers only in the double digits for a PSA 10. Has reached $2 million.

1969 Topps Nolan Ryan rookie card – Captures a pitching legend’s start. Low pop PSA 10s trade at $100,000 easily.

1974 Ted Williams final season card – Scarce and encapsulates a towering talent’s fondly remembered last at-bats. $10,000+ PSA 10s.

1990 Bowman Ken Griffey Jr. rookie – Icon recognizable to millions. Rare pristine copies break six figures.

1995 SP Authentic Ken Griffey Jr. refractors – Ultrasport modern rarities of ‘The Kid.’ Color versions are enormously scarce PSA 10s worth $50,000+.

2003 Bowman Chrome Albert Pujols and Miguel Cabrera rookies – Two legends emerged that year. The Cabrera ‘500 HR Club’ parallel especially collectible.

2011 Topps Update Mike Trout rookie – US star capturing a new generation’s interest. Reached $400 raw recently. BGS/PSA 10s still below $10k with upside.

2012 Bowman Chrome Mike Trout autograph rookie – The ultimate Trout, numbers surely in the dozens worldwide for true mint copies. $5,000K+ investment grade already during his prime.

As markets change rapidly, only relying on the timeless pillars of baseball card history and true conditional scarcity ensures investments stand the test of time for serious collectors. Those who properly authenticate, grade, and store classic 1950s/60s cards in pristine condition are set to profit handsomely for decades. Patience and avoiding overpaying hype is prudent.