Both don't expire, but just become inactive without a valid medical and can be paused for a longer time period and can get reactivated later?
Or is there a difference regarding expiration?
While the license does not expire, their are conditions attached to being able to exercise the privileges of the license. One of those is the requirement for fairly extensive refresher training if you haven't flown in 5 years or more.
It involves doing all of the exercises necessary to obtain the license, that you would need to demonstrate to a TC examiner. The difference is that you don't have to demonstrate them to an examiner as there is no formal exam, you do have to demonstrate them to an instructor and be signed off by the instructor. You also have to write the PSTAR air law exam, but that's a piece of cake.
The reality for a PPL, as I am, when letting your skills lapse beyond 5 years, is about 15 hours dual with an instructor.
Beech