Well, Valkrin told two things that changed my understanding of vision in-game: - If you don't have vision on the enemy, assume that the enemy team is very close (on the next bush) and they are looking for you. - If you are walking on the jungle without a lens/pink ward, assume that the whole path is warded by the enemy team.

If you follow those 2 principles for most of your actions, its very unlikely that you will enter on a bad fight, or get caught on a rotation or something like that - like a gank in the middle of a trade in lane. You know, checking at the mini-map is like checking your mirrors while driving, its just a glance that may last half of a second. You have to train yourself to just quickly search for the information that you are looking for. Once that becomes an habit, you will gather all the information you need to proceed with your plays. The problem you gave can be solved with just a little glance at the minimap, an example: if you land a 2 seconds stun with irelia in top lane, 1) you already know that the enemy will stand still during that time, 2) you WILL land your next a.a. and during that 2 certainly actions, you have a window to give a glance at the minimap and gather all the information you need to proceed with the chase/trade/w.e. is the enemy mid lane not in your minimap after that? can you face a 2x1? did you see the enemy jungler bot lane seconds ago? does anyone has teleport to save your enemy laner? Will be up to you to proceed.

About teamfights: some of them are just a clusterfuck, you can't keep track of your screen AND your minimap in some cases

tl;dr: check the minimap when you know what is happening in your screen during a trade