What is better repeat until or event:Wait()?

[MSDLF (Masol)]

In a repeat task.wait() until true
The script runs a task.wait() until something is met but this is not good for memory.

Now can you explain how exactly does a :Wait() works?

How does the computer or the hardware know what :Wait() is?

[GVectriz]

So RBXScriptSignal:Wait() yields the current thread until the event is triggered. It is better practice to use this.
Keep in mind though that this does not have a timeout parameter. You should be certain that your event will fire or it will continue to exist until the end of time or until you collect garbage.
Edit 2: You may alternatively find it useful to just add a new function entirely for that specific event. It could save you a headache in case something unexpected occurs. Quoting buildthomas here:
“prefer using structures of :Connect(…) in the cases that you can’t be sure that the event will actually fire, rather than sequential sections of code with :Wait() checkpoints, and then save the connection you get back from Connect, and disconnect it when you need it to be disconnected.”

[Send_Scripts (Scripty)]

:Wait() is by far better because the script just pauses, meanwhile a repeat is constantly using processing power to check the conditions to continue

[MSDLF (Masol)]

How does a script “just pauses” and what keeps track of it if the script itself is paused?

[itsLevande (Levande)]

Task scheduler will halt execution of the thread and then resume execution after the specified event is fired.

[MagmaBurnsV]

The idiom repeat task.wait() until is known as polling and is considered code smell. RBXScriptSignals already provide a more accurate and performant solution so you should always be using events wherever possible.

As for :Wait(), my personal advice would be to steer clear from actively yielding your code because it introduces the issue of having your code unintentionally halt or hang.

A more robust way would be to use the given :Connect() and :Once() methods for RBXScriptSignals and separate your code into event-driven functions. Here’s an example I gave on another thread:

@MagmaBurnsV

Seperate Logic in Functions

local Player = game:GetService("Players").LocalPlayer

local function OnCharacterAdded(Character)
	
end

local function OnCharacterRemoving(Character)
	
end

if Player.Character then OnCharacterAdded(Player.Character) end

Player.CharacterAdded:Connect(OnCharacterAdded)
Player.CharacterRemoving:Connect(OnCharacterRemoving)

[MSDLF (Masol)]

How do we know :Wait() itself isn’t polling?

[Send_Scripts (Scripty)]

A simple google search could of answered this for you:

Handling Events

[MSDLF (Masol)]

I’ve read that already. Don’t be snarky.

I was already wondering if :wait() uses polling itself or not.