as everyone has stated, you cant keep the plates. must be handed into one of the licensing places for storage til you have another vehicle to put them on. the usual $18.40 for change of plates, $14.50 to re-issue the plates you had in storage. you dont need to remember the date when you had them put in as it doesnt make it any easier to find them. if they have stored the plates correctly - which is usually in alphabetical order - then they should have no problems finding it. yes if they do lose your plates they will cover the cost of a remake, which happens from time to time.