Attached is a document I created on assurance of salvation if anyone is interested.
Regarding the original op's question, I find it bizarre that some groups think you can lose your salvation, yet re-gain it.
It seems like if Hebrews 6 says what they think it says, that would be an impossibility, and that those who lost their salvation have no hope whatsoever. If their view that it is speaking about that is correct, then there are no do-overs.
I do not think Hebrews 6 is saying what they claim it is, though. I just won't spend time arguing with the ones who claim you can lose your salvation.
I am not into fear and condemnation theology. I don't believe that a Christian can do works based on love if losing your salvation is a possibility, with the exception of some Arminians who believe you can intentionally and defiantly choose to walk away. I don't think those individuals necessarily have a fear and condemnation mentality, despite the fact that I disagree with them, but many on the forums do have a fear and condemnation mentality (thinking believers are still subject to condemnation).