How can i print how long it took for everything in the game to load for a player?

#####[Important fixes]

First of all, you need to get rid of your while loop. It's redundant.

Secondly, compare the RequestQueueSize with the proper constructor: ==

##------------- #####[Tick] Now, for this you should take advantage of the tick function.

Here is an example of it's usage:

local before = tick(); --Before the action
print("Hello world");
local after = tick(); --After the action
print(after-before) --Difference between the two

##------------- #####[Application] To apply this to your case, define a tick function proceeding & preceding the repeat loop :)

local player = game.Players.LocalPlayer
repeat wait() until player.Character
local character = player.Character
local before = tick(); --Preceding tick function

repeat wait() until game.ContentProvider.RequestQueueSize == 0

local after = tick(); --Proceeding tick function
print("it took "..after-before.." to load");