I ordered 4 units of L3+ from Bitmain on July. They should deliver me form 21.9. You can count that around 10,000 devices will be plugged in in October which will rise difficulty for around 5000. I think they received orders in August too which will ship in October. I think you can count you will get 50% from what you see now in calculators in November. Other factor is price which was going up from 45 to 90 USD but now after China ICO ban and rumors that China will ban Crypto exchanges it drops to 65 USD. I hope price of Ltc will go to 100 but can not guarantee that. Bitmain has Dash machine D3 which shows crazy good result in calculators of mining profitability but with that D3 you must also count that there will be difficulty increase with every new wave of orders. If I didn't buy 4 L3+ devices I would order D3. About Litecoin you can see profitability here:
https://www.cryptocompare.com/mining/calculator/ltc?HashingPower=504&HashingUnit=MH%2Fs&PowerConsumption=1200&CostPerkWh=0.075.
Many thanks for your reply. The way the difficulty is increasing (and will be increasing after all those L3+ miners go live) makes me think it's not really worth buying it... You have already ordered yours and it will come soon. If I want to order now, well, I can't (orders are currently closed, as usual), so I'll have to wait for the next batch. This means I will have to pre-pay $$$$ now, and my L3+ will arrive in December at the earliest, or in early 2018 if there are any issues, customs delays, etc. The difficulty then is expected to shoot to the sky, and LTC price is struggling ATM...
Given all of the above, I think I may have to abandon the mining idea, and just buy & HoDL for now. Currently seems more profitable and hassle-free...