When to use remote event or remote function?

Let's say you use remote events when you want something to run in another script that's not on the same type of script as the one you fire it from.

You use a remote function when you need a value returned by the function, a practical example:

localscript:

local remfunction = game.ReplicatedStorage.RemoteFunction

print(remfunction:InvokeServer())

script:

local x = "potato"
local remfunction = game.ReplicatedStorage.RemoteFunction

local function returnpotato()
	return x
end

remfunction.OnServerInvoke = returnpotato()

The local script in the above example would print "potato".