Why mining is not wort the time?

[DeathAndTaxes]

Unless you have A VERY powerful ASIC you will never get a ROI

Please do the math. ROI depends on both cost and return. You can get a positive ROI with a measly block erupter if you can find one cheap enough.

And you can possibly never show a positive return with the largest possible rig if you pay too much.

The factors for profitability are
price $/GH
efficiency J/GH
electricity cost: $ per kWh
exchange rate: USD per BTC
dificulty: both current and rate of growth

As odolvlobo, said the size of the rig doesn't make any difference.  It would be like saying "you will never show a profit unless you buy a LOT of facebook stock".  No you can profit with a single share, and you could also lose 100% with a million shares.  What matters is the price you buy at the price you sell at.

[milkthecow]

Thank you all for insightful replies!

[galbros]

Regarding ROI - mining is just speculating on bitcoin in a different way.  Right now you will at best break even mining, so by mining you are essentially saying that you think the price of BTC will rise.  That is the same thing as simply taking the same amount of money and buying some BTC.  However, with mining there is less of a trail to you of how you got your BTC versus an exchange.

If you look back on this tread there have always been people saying mining is not profitable - and they were right - it wasn't profitable at BTC prices of those times, but it damn sure was in hindsight.  Hence my point that mining is speculating just in a different way.

For a non-technical newbie, probably the best way to see if mining will work for you is something like Bitminter.  It is both a pool and a miner application and can give you a good estimate of how many BTC you will get with your configuration.

Good Luck!