Hello friends.

On this guide I will be sharing with you all of my knowledge about what summoner skills you should use in order to maximize your effectiveness to the game.

First of all - Flash:
When should I pick it? - Always.
Okay, but WHY should I pick it? - it's defensive and offensive benefits cannot be matched by any other summoner skill.
Alright, Wait, What?
A.It helps you get out from sticky substitution such as: ganks, an 'all in' by your opponents, offensive tower dives or even do dodge an hard Crowd Control that potentially will lead to your death.
B.It can be used offensively: For example, a flash bubble or flash flay can easily lead for a kill.
C.Flash the only skills that provides the ability to 'outplay' your opponent. For Example, you can flash thresh's hook as a Nami, land a close range Tidal Wave on both ADC and Support, following up with a bubble. Plays like this provide a solid gold lead to your team and could not be executed without a flash.

Now, for the riddle itself: Exhaust or Ignite ?
To remain things simple: Ignite is picked in order to increase kill pressure during the laning phase, while Exhaust is picked in order to assist you to defend your AD and AP carries during the mid-late game. Therefore, if your goal is to shut down the opponent bottom-lane you should pick ignite But, if your goal is to prevent the opponent's Assassin from bursting your AD or AP carry during a team fight - you should pick exhaust.

In-dept thoughts behind summoner skills picks:
On this part, I will share my way of decision making between exhaust and ignite.
The conflict about picking exhaust or ignite is divided into two main functions:
Laning Phase and Team fights. While Ignite provides you a higher kill pressure on lane, especially against a healing support, exhaust is a better late game summoner skill. The conflict will always exist yet, the answer is simple: You should pick exhaust when the opponent team has damage threats (such as Zed, Katarina or even Syndra) that you believe has the potential to burst your ADC before he can put any damage. In this case, even if your AD carry came out fed out of the lane, he wouldn't be able to use it's damage potential.

Moreover, there are match-ups that you cannot win a straight 2vs2 scenario unless the opponents perform very poorly. For example, when playing as Vayne Alistar bottom lane against a Lucian Braum, the odds of Alistar Vayne getting a kill by themselves is most unlikely. Therefor an Exhaust is recommended. If we look the other way around, as the Braum I would probably pick an Ignite for the same reasons. Also, there is always the factor that Vayne Scales better into the late game, so picking a defensive summoner skill as her support can prevent her death during the laning phase plus the mid-late game. Again, if we look the other way around, as the Braum I would get ignite to shut the Vayne down as early as I can.

Another Option as Duo-Bottom lane is to use Heal on the support and Cleanse on the ADC.
This option is harder to synchronize and not recommended during SoloQ games.
It benefits mostly against a heavy Crowd Control team, Cleanse breaks the main initiation (Leona Ultimate for example).
Put it in your minds that in most cases using Heal and Cleanse is weaker than Exhaust or Ignite during the laning phase.yet, when played correctly it has a very high potential during team fights.I recommend using Peeling supports such as Janna, Nami or even Braum for this tactic.