Here's what I do.

Mine the most profitable coin. With the profits buy your preferred alt-coin for speculating. Bills are paid and you have your coins.

The other way is to mine your preferred alt-coin at a loss, meaning that, you pay more money towards your electric bill, than you would if you bought the coins. Time/money/electricity is wasted and you end up with less coins for your money and a lot more wear and tear on your hardware.

TL;DR, If the coin you plan on mining isn't profitable, buy it instead of wasting resources trying to attain it.