Well, first it depends on the stake, site, and if it's FR or 6max
I play only FR right now and I'm confortable playing with just 20 BI's up to NL1000 at weak sites.
But my regular grind is NL100 and NL200, so I have a way more BI's to this one.
Savings: if you want to play poker fulltime, you should care more of trying to improve your game, not the bad runs you will suffer due variance. At FR if you know your opponents well you can make some big laydowns (for example a KK pf fold), so I dont always cry for "coolers" when it happens, most players cry a lot of coolers, but in fact they could have folded or played it better. So, 2 months is huge savings management for me I guess.
Just avoid PokerStars and you should be fine with 20 BI's for FR and 30 BI's for 6max. (assuming you play like 4-10 tables, if you play more, you need more, of course)
Sorry for my English and hope it helps,
Peace and good luck at the tables