Hand 1 I play exactly the same, don't see any problems there. Just take the free card for the straight and check when checked too. There isn't any value in a river bet.

Edit : thought you checked the turn, I dunno how often I bet this. Sometimes I would like to but don't

Hand 2, easy call. People with no money tend to flounder it away often you will see another ace or just complete rubbish.

Hand 3, this is the difficult one. I don't see any point to push UTG out. He isn't folding a better hand and there are no outs that you can clear up. I don't really know what to say about the hand and your position with CO though. My guess is he has an A, but im not sure. As it goes he may have bet flop with nut A draw, and paired onturn. In my opinion a raise serves no purpose and I think both calling and folding have their merits.

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