I feel like it is an instinctive aspect of the game, but I was wondering if there was a, for lack of a better word, "formula" in which a team starts to group up in order to push to win.
Hmm, a misconception is that you have to have a teamfight. League of Legends allow you the flexibility to capture objectives without ever having to teamfight. A simplified case could be one team trying to baron, and the other team decides they can't contest baron so they push a lane hard. After baron, the team decides they lost too much to try defending, so they will go push a different lane themselves and it's a base race. No teamfights, no anything else.
Ultimately the laning phase ends when one team decides to group up (generally mid) and take a tower as an objective rather than going for dragon/baron. At that point they are saying, "We are not going to just farm the lane anymore. We want to push to your nexus. Try to stop us." The other team then has to decide to ignore it (generally ill-advised since a 5-man team at this point can easily tower dive, win a fight 5v4 or 5v3, then push as 5, while one champion is not going to be able to push as fast by themselves or even as a 2 man.
Getting objectives "phase" is always happening until one team won through surrender vote or the nexus is destroyed. Objectives in League of Legends can be broken down simply as: 1) Destroy enemy Nexus 2) Destroy enemy nexus towers 3) Destroy at least one enemy inhibitor 4) Destroy at least one enemy inhibitor tower 5) Destroy at least one middle tower 6) Destroy at least one outer tower 7) Gather gold and experience to help you accomplish the above objectives
This is the simplest and minimum requirement of the game. Ultimately you want to destroy the enemy nexus, however it has a prerequisite that the inhibitor must be destroyed and both nexus towers are destroyed. To destroy an inhibitor you first have to destroy the tower protecting that inhibitor, and so forth. Gold and experience are your resources to help you accomplish the objectives. Everything else, supports that as champion kills, CS, dragon, baron all does just that for you and your team.
There is no exact formula for when the laning phase ends, but there are some clues:
One team tries to take dragon. Dragon is big money, and it's generally to your advantage to break away from lane and help or hinder dragon attempts. If this happens early enough, laning may continue after this.
Your lane's tower is destroyed. This causes the team that broke the tower to roam more, prompting team-fights.
Very fast lane clears. If you can clear your lane in 2-3 seconds, then zoning, harassment, etc is very hard. This effectively ends the laning phase.
In general, the laning phase is always over by the 30 minute mark.
I'm more of the notion that the teamfight starts when 1 or 2 towers are down. And the champions that are laning in that area are free to roam around, either because there tower is down or because the enemy tower is down. Some carries might still stay and farm, but others like top for example can come down to help take down mid. After some little grouping of 2-3 people start, the other team will do the same making the focus on team fights more important. Because you can't win 1 vs 4 ect...
These days, League turned from focusing on teamfights to small objective, thus the game became more tactical.
The laning phase ends about the 25-27 minute mark in most games. There are many ways in which it can end:
- jungler sticks to a lane
- one of the teams goes for a dragon or baron
- players start roaming and doing 2-3 men ganks
- turret gets destroyed (with the exception of destroying it before 10-12 minutes)
- the minion waves are cleared almost instantly
- one is outlaned, outfarmed, outplayed, harassed and zoned badly
- in my opinion lp is over the second one has bought 1 tier 3 item and another expensive one (can be contested)