To leave seeds or not to leave seeds (in the cage)? That is the question. Whether 'tis nobler to suffer the "tweets" and "acks" of outrageous fortune... But seriously: I agree with whoever said (above) that it's best to leave some seeds/pellets/combination of the two in the cage at all times. Budgies can starve to death if they don't understand that something is food or if they really don't like it.
Speaking of which, it's important to shake off or blow off the seed hulls several times a day; a food dish might look full, to us, but actually be nothing but empty hulls.