This is perhaps the most confusing part of larceny.  To be guilty of any of the larceny crimes, you must have intended to permanently deprive the other person of the property.  If your intent was to keep the property or money long enough that a major portion of its value or benefit is lost, this also counts as a permanent deprivation.

It doesn’t matter if they are actually permanently deprived.  Think of getting caught just outside a store for stealing and, after you are caught, promising to just return the property.  This is still a larceny.

It does matter, however, if that was never your true intent.  In other words, if you took your roommates car to get to class, always intending to drive it back after, it’s possible you are not guilty of any larceny.