Past laning...

I do very well during laning, but it seems to fall apart after that.

1. When we get to team fights, do you break off to stop an enemy split push, or do you stay with your team and focus on the team fight?

2. If you push a lane while no team fight is going on, and your team fully commits to a team fight while you're up lane, is it your fault for not being with them or theirs for committing while you were gone?

3. When I leave my lane to help a struggling team mate I almost always end up losing my turret before I can get back. Do you have to have teleport to pull this off affectively?

Thanks for any help.