Small starting pairs have many problems in hold ’em. One reason they’re often unprofitable is that they sometimes become no pair whatsoever!
If you hold a medium pair like 8♥ 8♠ and the board is 2♦ K♠ 4♣ 4♦ K♣, you hold a potentially commanding two pair, kings over eights. But, with that identical board, if you hold 3♥ 3♠, you have the same two pair everyone else does — kings over fours — with a three kicker.
Remember, the rank of non-premium pairs matters. There are many other reasons for this, too, beyond the disaster discussed above. You should often automatically fold small pairs in early positions — in both limit and no-limit hold ’em games. Especially in raked games, deuces through fives tend to be unprofitable when played from early positions.— MC