ROI is difficult to determine because the hash rate increases on a regular basis, the price of Litecoin fluctuates and of course electric rates are dependent on where you live. However, over the last week my two Antminer L3+ have been making approximately $35/day before electric costs, this is nearly identical to what I see in the litecoinpool calculator.

I see a number of scenarios playing out over this next year:

1. LTC does not increase from today's price of $65 - I will not break even in 12 Months.
2. LTC prices increase in accordance with an approximate 15% hash rate increase - Break even in 5 months.
3. LTC prices increase slowly around $1/month and we see $76 LTC next October (again assuming 15% difficulty increase) - Break even in 12 months
4. LTC prices tank or hash rate increases or LTC prices drop dramatically - I have a pretty nice Garbage Shed!

Plenty of other scenarios could play out as well. Ultimately, I think the adage don't invest what you can't afford to lose applies here as well. If it works out that would be fantastic, if not it was a fun project and I learned a lot.