Utilization is the price of liquidity

A market has 50 million supplied and 45 million borrowed. What can all its lenders withdraw between them right now?

• 45 million, the amount borrowed
• 5 million, the idle cash
• 50 million, because every lender's balance is backed

You supply to a market and also borrow against that supply. The pool has plenty of idle cash. What else can stop you withdrawing everything?

• The protocol's reserve factor
• The market's average utilization across chains
• Your health factor, which must stay at or above 1 after the withdrawal