I believe most national authorities will require you to submit your logbook at some stage to verify experience requirements prior to the award of additional ratings etc. Certainly here in Belgium it is a requirement that each flight is recorded and countersigned by your instructor prior to the issue of a PPL.
In addition each skills test (PPL, CPL etc) must be seperately annotated in the book and countersigned by the examiner.
I know of some non Belgian pilots who have fallen foul of the CAA here and have had to spend a considerable amount of time chasing down signatures and details.
So it would be in your best interest to record everything now and keep it maintained. It's also a good idea to record all notes in your logbook in English or at least be prepared to provide a certified translation if required.