This question doesn't really belong here, but it is a telling sign that since the last 4 weeks alone the difficulty has jumped a factor 2.5 (!) (https://bitinfocharts.com/comparison/litecoin-difficulty.html#3m) Right now you would earn 2LTC/mo or ca 500$/mo. That's still not bad (before december, if you held on to the coins, would have earned 1250$/mo!, that's why it is so important to come in as early as possible). But by end march that could easily have dropped to halve or less, and then it depends on where LTC goes, it if halves too, then go figure, it may take a loooong time to recoup the cost. Of course, if LTC goes to 1000$ then that would help a lot. Note that difficulty also swings with the price as some big miners move in/out depending on profitability.