To adjust how much Plum saves type 'mood' or select 'update mood' on the home menu.
By default, Plum's mood is 'Normal'.
If you want to save more, you can change it to:
'Eager' (25% more)
'Ambitious' (50% more).
If you want to save less, you can change it to:
'Chilled' (25% less)
'Shy' (50% less).