I'd assume in a retirement you'll have a set amount to withdraw each month for your monthly income. So for example, lets just say I need $2,000 a month from LC. I would set my BlueVestment account to maintain a minimum of $2,000 in cash. Once it hits that $2,000 in cash, then it will start investing again. As soon as I make my monthly withdrawal, it will start over in saving up the cash. To do this most effectively, you'll want to make sure that you get at least that amount ($2,000 in this example) each month in interest and principal payments.
That's just what I assume I'll do. But I'm a long ways off from being able to withdraw from my LC IRA.