Tournament Bankroll ?

[WSOPstar2B]

So far out of 76 tourneys I've got just under 11% ROI. I KNOW SMALL SAMPLE! Just mentioning this because some1 will answer saying if ur a loser than no bankroll is big enough. I'm not a winner but I'm not a loser either. But enuf of this.
Here's the question.
If I commit to playing 1 $50 & 1 $10 rebuy tourney 6 or 7 days a week, what should my starting bankroll be roughly?
And what point should I give serious consideration to moving up in buyins?
Please answer this helpfully and not w/an attitude.

[Exitonly]

atleast 2500 i'd say... but some more would be nice.

and as for moving up... you can 'take shots' w/ winnings if you dont need to withdraw from the roll to support yourself or anything... so then you can test the waters of higher stakes w/ winnings from the 10's/50's.

[benneh]

I take the SNG approach, and like to have at least 50 buyins for whatever level i'm playing it. More for the rebuys, of course.