Your maximum bet size in Blackjack should depend on your bankroll, risk tolerance, and the game conditions. A good guideline is to limit your bet to about 1-2% of your bankroll per hand. For example, with a $1,000 bankroll, your maximum bet would be around $10 to $20. If you're comfortable with more risk, you can adjust your bet size accordingly, but never go above what you can afford to lose. It's also important to consider the table’s limits and avoid betting large amounts simply because they’re allowed. If you're using strategies like card counting, you may increase your bet when the count is favorable, but this requires skill and attention. The key is to play conservatively, avoid chasing losses, and make adjustments only as your bankroll allows.