Honestly, NEVER!
My bankroll is Precious, and I never risk going broke, it might sound boring but I stick to what I learned years ago, you never put your entire bankroll at risk.
If you want to play for huge amounts then fine but before you do, you had better have 100 X the buy in to play the game.
There are two ways to do this,
1, Wait until your bankroll grows sufficiently to play in higher stakes.
2. Deposit smaller amounts on a monthly basis so it grows every month.
I prefer option 1. and play in low stake games until I build it high enough to play for higher stakes, mainly because I do not intend to become rich over night, that's for dreamers. I play simply because I love to play and it does not cost me a penny, I leave my dreams for the bedroom, not the Poker Table.
When the fun Stops, STOP!