A characteristic of addiction is the need for stock, whether it is cigarettes, alcohol or series. There should always be a ‘stash’ present, a supply for personal use. For me that is a to-watch list with at least five series. And a 'keep the best for last' for extra pleasure.
But what if the source threatens to dry up? Then there is always the possibility of watching the best series again. Actually, series are a fleeting commodity. Music is different. For example, I have listened to Pink Floyd's album Dark Side of the Moon many times. Comparing music with series is like comparing apples and oranges, but a good series can still move me more than once. It helps that I often do not remember the storyline in detail. It may also be that the storyline plays a subordinate role. IMDB has a list of series that are recommended to watch again. I have seen the vast majority.
I will elaborate on a number of series that I have watched at least twice.
Black Mirror
This series paints a sometimes absurd picture of the future. But it is striking that many themes are or have become reality. Take the episode in which the main character reconnects with her deceased boyfriend. That is already possible thanks to AI. It is still in its infancy, but still. Or the episode in which mini-drones are used as a kind of swarm of bees, also closer than many people think. There is also an episode in which one is strongly dependent on assessments by other residents. That is indeed exaggerated, but assessments play an increasingly important role. The series stimulates the imagination.

Nashville
A must see series for every self-respecting lover of country and americana music. The story plays a subordinate role compared to the music. The special thing is that most of the songs were actually performed by the actors and actresses. The songs are on various playlists in Spotify. I really have to go to Nashville and surroundings to visit a few music cafes or attend a concert at The Grand Ole Opry. I have been to the US a few times and have been introduced to bands and music through the many country radio stations that you never hear here.

Peaky Blinders
Birmingham, city of emerging industrialization after the First World War. Meet the Shelby family. In addition to all kinds of criminal activities, they run a café in Birmingham. How convenient, they all do not turn down a good daily drink. This is also due to the terrible First World War in which most family members fought in the trenches. Arthur Shelby in particular struggles with the consequences and that makes him unpredictable. The story, the acting, the scenario and especially the atmosphere result in a series to watch at least twice.

Star Trek: Voyager
In August 2024 I wrote a review about Star Trek: Discovery. In that review I honestly confessed that I am a Trekkie. However, I certainly do not watch all series again. I make an exception for Voyager. It may not even be the best of the Star Trek series, but the story appeals to the imagination. Because Starship Voyager has ended up at an immeasurable distance from Earth, it is questionable whether it can reach Earth again. That offers room to introduce many different species. It is actually a series 'from the old box' because the series ended in 2001, but with 172 episodes you will be busy for a while.

Mad Men.
I have seen Mad Men twice and am currently watching this series for the third time. The series paints a picture of the sixties of the twentieth century. The assassination of Kennedy, the Cuba crisis, the rise of the free-spirited hippies. All themes are addressed. It was a time of increasing prosperity, but also of unadulterated racism. What makes the series so beautiful is the atmosphere. This is partly due to the utensils, clothing, cars and architecture. Leading actor Don Draper, played by Jon Hamm, creates a wonderful character of a brilliant advertising executive. A mysterious, idiosyncratic and free-spirited man. All the co-stars deliver a great performance. A series never to be forgotten.

A few more examples without further explanation: Sons of Anarchy, House of Cards (2013), Breaking Bad, The Sopranos, Better Call Saul and Succession. I also recently started watching Game of Thrones, but for reasons that are unclear to me I stopped quite quickly.
Current series that I will definitely watch again in the future are Dexter: Original Sin, The Crown, Yellowstone (2018) and the prequels 1883 and 1923.
My list is far from complete, which series are on your shortlist?