WEIGHT
The best weight is very much based on feel. If you take multiple swings and the bat feels heavy or begins to drop, then it’s probably too heavy for your needs. Try holding the bat handle and extending your arm to your side. If you can’t hold the bat extended for 30 to 45 seconds, the bat might be too heavy for you.
Be sure to look at the “drop weight” as well. A bat’s drop is the measurement determined by subtracting the weight of the bat from its length. For example, a bat that weighs 20 ounces and is 30 inches long will have a drop of -10. The greater the drop weight, the lighter the bat.
Larger, stronger players tend to favor less of a drop weight, which can result in increased power. Smaller players can benefit from greater drop weight, which can help with bat speed.
"A common problem we see is a kid showing up to practice with a bat that’s too heavy. Sometimes parents will buy a heavier bat because they think it’ll last longer, but that’s not always the best for a youth player," says Lancianese, "when in doubt, buy the lightest bat that makes sense for your wallet."