I am a bit of a "newb" and I have searched the forums but still can't find any sort of threads which definitively answer/provide me tips & knowledge to the two questions I have.

1. Which cards allow you to keep your miles/bonuses once you cancel the card?

2. Can somebody link me some information on how to effectively churn cards or is it truly as simple as canceling and then re-apping 6+ months later?