I do this in The UK with about 1.5 TH/s to play with.
I mine across 4 pools for 2 reasons:
1) Regular income. Just in case 1 pool gets a bad block & grinds to a halt.
2) Sheer curiosity. An obsession with luck.
So far it's working.
I have a personal Bank Account with 2 Personal Credit Cards tied to it I have all marked off as 'business' ( I have like 6 Bank Accounts total so this isn't a biggy ).
Each pool pays into a separate wallet, & I sell what I've made every 2 weeks.
It pays the electricity & the credit cards ( including paying off debt & the odd IT repair cost ).
It's not big money, but better than a kick in the testicules.
I run:
Some sticks & an avalon3 for making some personal BTC ( that is not sold ).
A pencil-modded s1, a Coincraft Desk, and an Antminer s3, for 'business BTC' ( which I then sell ).
The golden rule is simply to not go over £1000 in debt. If you stay small any 'crash' won't wipe you out.
*shrugs* Works for me.