involuntary if they make a threat and articulate a plan
if they ask to go in for a tune-up (voluntary commitment), the length of stay is shorter because it's basically up to them to say they're ok to go
involuntary gets a longer length of stay because a judge issued an order for them to enter, so a psychiatrist has to determine when it's time to leave. most inpatient psych units have their frequent fliers trained for getting the 7-10 day rides every month. this keeps the beds filled with familiar patients and keeps the lights on.
