[Closed] A few more hands (0,5/1)

Made two posts this time since i got quite a few hands im uncertain about.

Hand 1
Okay calldown or should i fold it - flop/turn/river?

PartyPoker 0.50/1.00 Hold'em (10 handed) Recorded and converted with HandRecorder

Preflop: Hero is CO with A♦, A♥
UTG calls, 1 folds, UTG+2 calls, MP1 calls, 1 folds, MP3 calls, Hero raises, 2 folds, BB calls, UTG calls, UTG+2 calls, MP1 calls, MP3 calls.

Flop: (12.50 SB) 8♦, 5♠, Q♦ (6 players)
BB bets, UTG folds, UTG+2 calls, MP1 folds, MP3 folds, Hero raises, BB 3-bets, UTG+2 calls, Hero calls.

Turn: (10.75 BB) J♣ (3 players)
BB bets, UTG+2 calls, Hero calls.

River: (13.75 BB) Q♠ (3 players)
BB bets, UTG+2 folds, Hero calls.

Final Pot: 15.75 BB.

Hand 2
Again a question followed by an example - semibluffing/bluff busted draw - should i c/f the river (played the hand before i read blinzlers response to a similar hand)?

PartyPoker 0.50/1.00 Hold'em (10 handed) Recorded and converted with HandRecorder

Preflop: Hero is SB with 5♠, 6♠
8 folds, Hero calls, BB raises, Hero calls.

Flop: (4.00 SB) 9♦, 7♠, 3♦ (2 players)
Hero checks, BB bets, Hero calls.

Turn: (3.00 BB) 5♣ (2 players)
Hero bets, BB calls.

River: (5.00 BB) T♥ (2 players)
Hero bets, BB folds.

Final Pot: 6.00 BB.

Hand 3
Too weak to fold with TPTK?

PartyPoker 0.50/1.00 Hold'em (8 handed) Recorded and converted with HandRecorder

Preflop: Hero is UTG+1 with A♥, Q♣
Hero raises, 4 folds, CO calls, SB 3-bets, 1 folds, Hero calls, CO calls.

Flop: (10.00 SB) T♣, Q♠, 4♣ (3 players)
SB checks, Hero bets, CO raises, SB 3-bets, Hero folds, CO calls.

Turn: (8.50 BB) 9♣ (2 players)
SB bets, CO calls.

River: (10.50 BB) J♥ (2 players)
SB bets, CO raises, SB calls.

Final Pot: 14.50 BB.

And beacuse i didn't get an answer in the other thread i will ask again:
Are there specific situations where i shouldn't cont. bet on the flop as the pre-flop agressor OOP or when checked to IP?

Thanks in advance