How do you count the amount of the same model existing in a game at once in a script?

I want it so that for every model named "Plant" gives 100 "Credits" per 1.5 seconds.

I have the actual money giving script done and perfect, it gives 10 credits every 1.5 seconds, now I want it to add 150 more credits per Plant that exists simultaneously in game.

I have it to where it prints whatever the value of "amount" is every time it adds Credits, it just continuously adds 150 to the already existing 150 making it go up to numbers like 1000 within seconds, this is because it is in a loop, but the script doesn't actually work unless it is in the loop.

Heres the script:

amount = 10
timedelay = 1.5
currencyname = "Credits"
teamcore = 0 -- ignore this

while true do 
	wait(timedelay)
	for i,v in pairs(game.Players:GetPlayers()) do
		if v:FindFirstChild("leaderstats") then
			v.leaderstats[currencyname].Value = v.leaderstats[currencyname].Value + amount
			local cash = workspace:FindFirstChild("Plant")
	if cash then
		yes = true 
				if yes == true then
					amount = amount + 150
					print(amount)
				end
			end
		end
	end
end

any help please?