Hi,
i'm never sure when to call down a 2nd pair. What reads do i need?
Is it bad for me when the turn pairs?

Another thing is, what is a good turn + rivercard to call barrels? Normally it should be an undercard but on the otherhand villain should be less likely to barrel air on another low card.

Can we say that vs fish we can more often call 2nd pair on bad barreling cards (low cards) and regs are more likely to check there without a hand?

PokerStars - $14.69+$0.31|10/20 NL (2 max) - Holdem - 2 players
Hand converted by PokerTracker 4

SB: 500
Hero (BB): 500

SB posts SB 10, Hero posts BB 20

Pre Flop: (pot: 30) Hero has J 8

SB raises to 40, Hero calls 20

Flop: (80, 2 players) 3 8 Q
Hero checks, SB bets 40, Hero calls 40

Turn: (160, 2 players) 3
Hero checks, SB bets 80, Hero calls 80

River: (320, 2 players) 4
Hero checks, SB bets 200, Hero calls 200

Another 2 examples:

First one didnt look like a reg, he foldet 5/5 hands OOP so far.
And i have noe clue if i should give up or not. His small bets look strong but dont they give me the odds to call? Considering its the first hand he plays OOP and he 3bets it, i think he almost everytime has the care here. So how to play? Fold river?
And what if his bets were bigger? Should i then already fold on the flop?

PokerStars - $14.69+$0.31|15/30 NL (2 max) - Holdem - 2 players
Hand converted by PokerTracker 4

Hero (SB): 465
BB: 535

Hero posts SB 15, BB posts BB 30

Pre Flop: (pot: 45) Hero has T K

Hero raises to 60, BB raises to 120, Hero calls 60

Flop: (240, 2 players) A 5 T
BB bets 60, Hero calls 60

Turn: (360, 2 players) 8
BB bets 60, Hero calls 60

River: (480, 2 players) J
BB bets 295 and is all-in, Hero calls 225 and is all-in

2nd example:
The opponent had 2% roi over a good samplesize, so what to do on the turn? Call turn and fold to a 3rd barrel? Or should i already fold the turn because its a bad barrelcard for him?

PokerStars - $14.69+$0.31|10/20 NL (2 max) - Holdem - 2 players
Hand converted by PokerTracker 4

Hero (BB): 460
SB: 540

SB posts SB 10, Hero posts BB 20

Pre Flop: (pot: 30) Hero has K J

SB raises to 40, Hero calls 20

Flop: (80, 2 players) J A 5
Hero checks, SB bets 40, Hero calls 40

Turn: (160, 2 players) 2
Hero checks, SB bets 80, Hero calls 80

River: (320, 2 players) A
Hero bets 100, SB raises to 380 and is all-in, Hero calls 200 and is all-in

1. I'm folding river - bad runout for us good for him (turn pairing probably makes him less likely to barrel and when the flushdraw hits, clubs don't have to bluff)

2. I hate when they do it Vs this sizing I play the same but fold river. I put him on a strong range to make this small 3bet (until he proves me wrong, if it was a min3bet I would give him more funky hands), that hit this flop hard and is afraid we might fold. Nevertheless otf we have odds to call and try to suckout IMO

3. I don't like the block bet. I would check and probably call anything upto 160. If he shoves river I'm not sure.
FYI If he is a reg, there are probably not many "bad turns" for him to barrel (IMO many regs just blindly barrel A high boards - and rightfully so).