Like a lot of things in RPGdom, I think that "length of use" is probably one of the biggest points of departure for a lot of people's experience.
I agree, which is why I try to explain my experience at some point and emphasize that my insights are a way to run sandbox campaigns, not THE way.
Specific for myself it is more than that, as I have extensive experience trying to manage campaigns with other types of roleplaying like LARPS and MMORPGs (modded servers like for Bioware's NWN). For LARPs the fact that live action is the primary method of adjudication means I have to adopt a different set of techniques for directing LARP events. For MMORPGs, the fact that a software algorithm is doing most of the refereeing brought in a different set of techniques.
There is some overlap in technique but the combination for each is unique as well as it application. Each had its own point of departure as a result of making a different choice on how to adjudicate the campaign.
I'll admit that I do not reuse settings to any great extend. A campaign has a setting, and, by and large, a half life of about 1-2 years. At the end of that campaign, that setting is retired and probably never sees the light of day again. Even when I've used something like Forgotten Realms, each campaign is generally distinct enough that the events of one campaign have zero impact on another.
That preference works just as well as any other and provides crucial context for your preference as far as systems go.
For example, my Candlekeep Mysteries campaign resulted in the death of the Tarrasque as well as the Shadowfell being remade and light being brought back. It also resulted in the release of Zargon into the world again.
As a side note: I did destroy the Majestic Wilderlands once and retconned it later. However, I revived it briefly as an "alternate universe" version for when the group wanted to try D&D 4e. I attached the Dark Wilderlands write up I made before the campaign.
I figured that 24/7 fantasy superheroic feel that D&D 4e had would make this a good fit for this in a short campaign.
Which brings me to my second biggest impact on RPG's - half-life of groups. If you have a stable group that plays together for years or decades, you are going to have a radically different experience with RPG's than someone whose groups tend to have a half life measured in months or years. And that is really going to impact how you approach games.
While I have friends I have known for decades show up in successive campaigns, in general, each campaign has its own distinct group of players and characters and lasts for one or two years. I will then update my campaign notes and push the timeline forwards a year or two for the next campaign.
However I generally don't know where the next campaign will start. The players and I will talk about what they want to experience and what circumstances they want to start out in. Often it is a couple of distinct ideas. I will then outline three or four regions of the Wilderlands (and lately the Majestic Fantasy Realms) that fits their idea. They pick one and we finish up character generation.
I have mediocre records of my face-to-face campaign, but I have also been using VTTs since the late 2000s. With that I been keeping a pretty good log of the campaigns I run on-line. The notes themselves are still pretty terse.
For example, this is is what a campaign entry looks like .
Compare a blog entry I made about this campaign.
To another campaign two years later (lasted from July 2014 to August 2015)
Tim, Dan, Josh (Rhandom), and Ken all played in the Nomar campaign.
Compared to a campaign I am running now in 2025 where Josh is the only player from two above. However, I gained Dave an old from high school and college, and who played my Majestic Wilderlands multiple times.
While the above is set in my Majestic Fantasy Realms, it is in effect a reskinned version of the work I did for my Majestic Wilderlands, so it is more of a continuation rather than a brand new setting. Dave had no problem using what he knew from playing 20 years ago in the new campaign. In fact mocked me just tonight because I was tired and kept slipping up using my original MW names for cultures and deities rather than my MFR versions.
Hoped that clarifies how things work out with the way I run things.
Finally, I heard first-hand accounts of groups who played for decades with the same group of characters. And I am still not clear how that is managed on both side of the screen. With my campaigns, the players get to a point where they feel that they have accomplished what they wanted to do with their characters between a year and three years after the start of the campaign (with weekly or bi-weekly sessions). As a result the campaign has a stopping point that feel right. For the Nomar campaign, that point came when the inn was finished being built, which was the focus of the players for the last third of the campaign.