Any flying you do with an instructor is for the purpose of obtaining or re-validating a licence or rating; otherwise you don't need an instructor!
Perhaps being picky, but not entirely true, surely? ... eg having an instructor aboard for 3 t/offs and landings if out of 90 days currency for carrying passengers. Licence and rating would still be current (i.e. you could do the necessary solo) so not re-validating, and if you want company it can only be provided by an instructor, not a vanilla PPL.