Hello
I gonna answer that question correctly, before other classes use troll answer and and say wrong thing.
Let’s make that question by a main hunter, gonna make a more developped answer
That true example hunter can’t spam heal exept healing pet, but we got other toolkit in our spellbook.
Classes like Mage / Rogue / Warrior / Hunter ( i exclude death knight for that example due to the example ) is all based upon denying damage
So we don’t play around healing, but prevention :
- Mage tend to use magic shield to prevent damage and if a too high damage come to him, he will use iceblock and then run away
- Rogue will use feint to reduce a strong incoming damage if Cloack of shadow or evasion is on cooldown to reduce incoming damage by 30% for 5 sec ( feint got 15 sec cd)
- Warrior will tend to reflect spell or disarm / parry to prevent the ennemy offensive cooldown to be effective. Also he can prevent many spell or attack thank to his frequent stun
- Hunter will tend to run a lot and by using Survival tactics ( honor talent) to deny a Chaos bolt or to dispell himself a magic ( slow or dots). Also with binding shot and Bursting shot you will tend to counter mobility cooldown of your opponent. And since feignt death is on cooldown, in serious situation we will use turtle instead if we got no choice.
Also these classes in order to get their heal back, need to go out of combat to heal themself :
- Warrior when playing with no healer tend to play with Second Winds, to run out of his opponent and line for few sec and then go back
- Rogue tend to avoid combat and spam his potion healing even if it’s few to get back to 100%
- Hunter tend to go with camouflage, freeze trap his opponent and then feignt death to then use 6 seconds after FD camouflage to get healing back.
- Mage tend to CC and then invisibility to hide to the opposite of the player to eat food to take back.
But Shadowland helped us for those who don’t have a self healing systems.
In BFA Bandage was not usable in arena, and no one used them in any content due to their effectiveness and situtaion.
So when Blizzard was reading feedback i tried to bring back bandages back to the scene with that post :
And so they read it and 2 week after in shadowland bandages was useable in arena.
So now instead of waiting 6- 10 seconds for nothing behind pillar you will now be able to use bandage to get good benefit of it to your toolkit of survival to counter classes that can spam self healing.
But sometime all of these is not enought. But thank to shadowland with my hunter most of my problems is solved about survivability versus certain classes ( most of them, there’s still some of the meta classes you can’t do anything about it).
Necrolord.
Thank to Marileth soulbind, you can get a serious self healing on you with a shield when you drop under 50% health that give you 10% of your health a shield and Fleshcrafting ( 20% of you health as shield, but gonna be buffed in 9.0.5) when fully channeled can heal you 20% of your health.
Note that as hunter you can channel Fleshcraft while on Aspect of the Turtle due it’s not a spell that deal damage.
So to resume
Mage / Warrior / Rogue / Hunter / Death Knight can’t get spammable healing, so they have to play to prevent damage instead of tanking than healing.
The way to heal themself is to get out of combat and use talent or spell and run away from the fight a good amount of time to be ready to go in combat again.
Bandage is useable in Ranked PvP to reduce that disavantage of not able to spam healing themself.
Hope it as helped 
!
Oh and :
We are always the noob of somebody else, until you will hit the Rank 1 of everyone
So don’t push you down, keep yourself up because even top player learn new thing everyday
So it’s not a crime to learn and to ask question 
!