How to handle datastore failures?

So say this is my data that I would like to store, now I've read the info on the wikis about failures but since this doesn't auto save, how would I make sure a player gets notified that their data may not save? Should auto saving be implemented or not? And how would I make it so that if, in fact, the data may not save that it doesn't overwrite the players save file? Not understanding how to do this.

local ds = game:GetService("DataStoreService"):GetDataStore("stats")
statz={"Kills","WOS","Noobs"}
game.Players.PlayerAdded:connect(function(plyr)
	local a=Instance.new("NumberValue")
	a.Parent=plyr
	a.Name="leaderstats"
	for i=1,#statz do
		local stat=Instance.new("NumberValue")
		stat.Parent=a
		stat.Value=0
		stat.Name=statz[i]
	end
	local child=plyr.leaderstats:GetChildren()
	for i=1, #child do
		child[i].Value=ds:GetAsync(plyr.userId..child[i].Name)
	end
end)

game.Players.PlayerRemoving:connect(function(plyr)
	local child=plyr.leaderstats:GetChildren()
	for i=1, #child do
		child[i].Value=ds:SetAsync(plyr.userId..child[i].Name,child[i].Value)
	end
end)

You should make a backup datastore named something like backupstats and keep your data there. Then, when you set new data, edit it into stats first, and if it fails, set the stats back up to backupstats. But, if the save is successful, save the stats into backupstats too.