It was found that even by FinTech Mining Review conservative estimates you EASILY beak even within 6 months and may potentially double your earnings within the year.
Admittedly the difficulty rate is increasing at a high rate but the hashing power is too and becoming cheaper at a steeper rate. So whatever your approach is likely to be, if you apply the principal of reinvesting your earnings or at least a good portion of your earnings during a period as soon as the hashing price falls (the cost per Ghs has never gone up) then you will make a a small fortune.
What I am showing is when you treat mining as you would with any proper business and not a gimmick you'll certainly reap the rewards from it. You need to take the attitude that 6 months, a year or perhaps a three years is not a great deal of time (especially if you are earning money whilst you sleep) and I believe you should definitely spend an hour or two on excel and on line to ensure that you take a proper approach.