This has been a problem that has been vexing me for a while, and it manifested again in my most recent game in which I played Black:
[FEN ""] 1. d4 d5 2. c4 c6 3. Nc3 Nf6 4. Nf3 e6 5. Bg5 h6 6. Bh4 Be7 7. cxd5 cxd5 8. e3 Qb6 9. Qc2 O-O 10. Bd3 Nc6 11. O-O Bd7 12. a3 Na5 13. b4 Nc4 14. Bxc4 dxc4 15. Ne5 Rfd8 16. Rfc1 Rac8 17. f4 Kf8 18. f5 exf5 19. Nxd7+ Rxd7 20. Qxf5 a6 21. Bxf6 Bxf6 22. Qxd7 Qc6 23. Qxc8+ Qxc8 24. Nd5 Qe6 25. Nxf6 Qxe3+ 26. Kh1 gxf6 27. Rxc4 b5 28. Rc8+ Ke7 29. d5 Qd4 30. Re1+ Kd7 31. Rcc1 Qxd5 32. Red1 Qxd1+ 33. Rxd1+ Ke6 34. Rc1 Kd5 35. Rc5+ Kd6 36. g4 Kd7 1-0
On move 6 I was forced to choose between breaking the pin on my knight or weakening my kingside. I chose to ignore the pin, which then furnished my opponent's position with many tactical opportunities. So, are there any rules or principles regarding pins, such as you should always break a pin as long as you are not immediately losing material? In games like this, how do you make the right decision when the threat is not immediately tactical, but will manifest later? How do you measure breaking the pin against other possible goods like development, king safety, and positional advantages?