With these hands don't draw any cards:
Royal flush
Straight flush
4 of a kind
Full House
Flush
Straight
With these hands draw one card:
4 cards to a royal flush
4 cards to a straight flush
4 cards to an outside straight (unless you have a low pair, then keep the low pair)
2 pair
4 cards to a flush
With these hands draw two cards:
3 cards to a royal flush
3 cards to a straight flush
3 of a kind
With these hands draw three cards:
Pair of Jacks or Better (Never throw this away unless you have at least 4 to a straight flush)
1 pair
2 high cards
KT, QT or JT suited
With these hands draw four cards:
1 high card |