Is there a way to make this safe and efficient?

For the past week, I've been noticing I lost my progress with this script. Can I use pcall or something to fix it? Thanks.

function onPlayerEntered(player)
wait()-- Change to wait for player longer.
player:WaitForDataReady()
repeat wait() until player:FindFirstChild("leaderstats")
if player.DataReady then
if player:findFirstChild("leaderstats") then
local score = player.leaderstats:GetChildren()
for i = 1,#score do
local ScoreLoaded = player:LoadNumber(score[i].Name)
wait()
if ScoreLoaded ~= 0 then
score[i].Value = ScoreLoaded
end
end
end
end
end

function onPlayerLeaving(player)
if player:findFirstChild("leaderstats") then
local score = player.leaderstats:GetChildren()
for i = 1,#score do
player:SaveNumber(score[i].Name,score[i].Value)
end
end
end

game.Players.PlayerAdded:connect(onPlayerEntered)
game.Players.PlayerRemoving:connect(onPlayerLeaving)

Hopefully this will help:

local Players = game:GetService("Players")
Players.PlayerAdded:connect(function(player)
	wait()-- Change to wait for player longer.
	player:WaitForDataReady()
	repeat wait() until pcall(function() return player["leaderstats"] end)
	if player.DataReady then
		if pcall(function() return player["leaderstats"] end) then
			local score = player.leaderstats:GetChildren()
			for _,v in pairs(score) do
				local c_s = score[v.Name]
				local ScoreLoaded = player:LoadNumber(c_s.Name)
				wait()
				if ScoreLoaded ~= 0 then
					c_s.Value = ScoreLoaded
				end
			end
		end
	end	
end)
Players.PlayerRemoving:connect(function(player)
	if pcall(function() return player["leaderstats"] end) then
		local score = player.leaderstats:GetChildren()
		for _,v in pairs(score) do
			local c_s = score[v.Name]
			player:SaveNumber(c_s.Name,c_s.Value)
		end
	end
end)

Only 28 lines. One less than the original. This is also way more reliable, efficient, and it should work.