When should you leave your lane to help the team and sacrifice your tower?
In a recent game, I was playing against a Fiora at top lane and was pretty even but Fiora would constantly return to lane, push the lane with her Tiamat and I'd push back. The rest of the team was getting into fights in bot jungle and mid but I thought I should focus on farming so I don't fall too far behind the enemy team that was getting fed.
At what point do I let Fiora have the tower and hang out mid/bot-jungle to save my team? There have been games like this in the past where I've left lane to help while the enemy top laner ends up pushing to the 2nd top tower because the team is spread too thin dealing with the other 4 enemies besides top lane.