User blog comment:Soulreaper1234/What's up with Ichigo and his BANKAI, is it in constant release?/@comment-1268838-20100915120243

Well, sure, Ichigo's Bankai has been active for quite some time - at least three months and a day. However, to say that it is a "constant release Bankai" implies that he is incapable of turning it on and off at will, as is the case with his Shikai. As for how he's able to keep it on for so long, Lia already explained the power compression power - that, combined with his ridiculous amount of spiritual power makes it no surprise that he could maintain it. Who knows? Maybe he can keep it active forever if he really wanted to, but that's anybody's guess.