Off and one, when they offer me a deal.
Consumer Reports for decades.
Consumer Reports for me as well, but I miss the detailed reviews of foods and cars that they used to do. Lots of wasted “graphic” space and social and health issues instead of product reviews.
I used to like Consumer Reports but never subscribed. A lot of what they review are American models or products unavailable in Canada. Local laws meant they added a “Canada Extra” supplement which only slightly compensated for this.
I bought an issue recently because the cover mentioned three (or so) products I would be interested to see reviewed. All three products were shoehorned on a one page “Things We’re Working On” summarizing ratings for a mere six or seven products. None had articles or even a brief discussion. I kind of felt ripped off. There review of stuff like cars is still useful.
(The) New Scientist, since some time in the 80s and still going strong, having migrated to the iPad edition.
Ones I’ve dropped over the years (or which have died) include Scientific American, Time, the Skeptical Inquirer, A New Day (Jethro Tull fanzine), RAM (Rock Australia Magazine), Choice … I’m sure there must have been others.
Trains THE magazine of railroading
Subscriber since 1967
For me it’s The New Yorker, going back as long as I can remember. I’m glad to see a few others have mentioned it. There have been other magazines with comparably high literary and journalistic standards, most of them now defunct, but overall, The New Yorker stands alone. A great example of the kind of thing that endears it to me is Pulitzer Prize winning journalist Elizabeth Kolbert’s magnificent three-part series on climate change, The Climate of Man, back in 2005, which won the 2006 National Magazine Award for Public Interest. The title itself is a fitting reference to the anthropocene, literally a new geological era shaped by the impact of human activities on the environment.
The Economist, if you count electronic subscriptions. Given my wandering life, I have not always had reliable postal service so I have gone years without a subscription, but this is the one magazine I come back to.
National Geographic. My collection goes back just a couple of decades, but my brother inherited the larger collection from our father (our grandfather started it). He has every issue from 1888 to present.
https://www.prospectmagazine.co.uk/
I’ve had a subscription since they started. I don’t always keep up with each issue as it arrives, I’m ashamed to admit.
This is me. Although I will probably cancel because I don’t really read much of it any more.
American Rifleman. Does that count as I get it for free with my life member status in the NRA? But I have been getting it continuously since 1979.
Sports Illustrated and Reader’s Digest.
It was Playboy, but they stopped publishing.
Anything counts. I’m always surprised at the popularity of the New Yorker and National Geographic. I love the New Yorker cartoons, sometimes think the articles and poetry are good, not always. I have subscribed.
I was going to say the world has changed a lot since NatGeo sponsored explorers and expeditions, but probably geography itself (but not its study) hasn’t much changed over just a few hundred years. 
All of my favorite magazines have stopped printing years ago. Cracked in 2007. PC Magazine and Computer Shopper in 2009. Wizard and Toyfare in 2011. PC World in 2013. And now Entertainment Weekly in 2022.
Me or my parents had subscribed to Popular Science since the early 60s and Popular Mechanics since the 40s but I ended up canceling them both after they had multiple revisions in format post-2000.
Also my family were regular subscribers to TV Guide until they stopped publishing the local digest-sized editions in 2005.
My aunt probably holds the record in my family–she had over 100 years of National Geographic magazines in her home before she had to move to a nursing home in 2018. I am not sure what my cousins did with all the back issues. And she apparently still subscribes to it and reads it monthly.
Air & Space magazine since 1986, it is however a shadow of it’s former self.
NG is a big favorite for owning stacks of but honestly, how many people go back and read one of the ancient issues except as a curiosity? As I told a friend when I gave him all mine before moving, “Without an index it’s just a pile of magazines.”
I bought the complete disc set they offered come fifteen years back because it does have an index, but I use it on;y occasionally.
Collectible Automobile since the late 1980s. Published bimonthly. Bound, not stapled, printed on high quality paper with no outside advertising. Have them lined up on a bookshelf. Wife asks why I keep them I say it is for when I am old and feeble I can re-read them.
20 years National Geographic until I felt they were getting too political.
Consumer reports for many years, then I was realizing they never really reviewed anything I use on a regular basis or would even buy. Along with many of the brands that are tested are not even available where I live. Final straw was a year subscription was no longer 12 issues.
I guess I’ve been getting Skeptic Magazine for about 30 years now. I have learned something new in just about every issue.
In terms of current subscriptions that I actively re-subscribe to, it’s The Atlantic, for about 25 years. I send the hard copy to my dad, while I use the digital.
The longest of my life was probably Sports Illustrated, but stopped that one about 15 years ago.
Someone who I don’t know has been sending me Reader’s Digest for longer than either of those, but I rarely take it out of the plastic wrap.
Vanity Fair
Smithsonian
National Geographic
Kiplinger’s
RS