Once you have obtained your JAA PPL it remains valid for five years provided that you keep your medical certificate and fly enough hours each year to keep your certificate of experience current. Your certificate of experience is part of your licence and is valid for two years. To revalidate the certificate of experience you need to fly 12 hours in the 12 months preceding the expiry date, including a 1 hour flight with a flight instructor.
Of this requirement, at least 6 hours must be as pilot-in-command (P1) as opposed to pilot under tuition (P.u/t). Alternatively, while the certificate is still valid, you can take a 'proficiency check' with a flight examiner. If the certificate expires without being revalidated, you can 'renew' your certificate by taking a 'skill test' (flight test) with a flight examiner.
The medical certificate examination may be carried out up to 45 days before the expiry date and a consecutive period of validity will be granted.
During the period of vailidity of your JAA PPL the privilege to carry passengers depends on having flown at least three takeoffs and landings within the last 90 days. An essential feature of your JAA PPL is that you can not fly for 'hire or reward'. In other words you can not charge members of the public for pleasure flights or get paid to take aerial photographs etc.