I bought an eleven-inch MacBook Air in 2015 and a thirteen-inch Air in 2016. Both have served me well, with the latter as a desktop machine plugged into an external monitor. The eleven-inch Air has the base 4GB of memory while the thirteen-inch has what was by that time (2016) the base 8GB memory.
Last year the 4GB machine began running into problems. I'd kept it at Mojave OS because I preferred an older (32bit) version of Pages compatible with that OS. And I had older Office software running on it, too. But then I found I was no longer able to access my Yahoo e-mail account via Apple Mail (OS too old), which was a bit of a pain, but accessing Yahoo via the web was nevertheless still possible. A couple of other accessing issues (with my wi-fi setup) too, meant I eventually upgraded to Mavericks on the eleven-inch Air. To my disappointment, Mavericks was still not recent enough to give me back my Apple Mail conduit to Yahoo though, and I also lost use of my old Pages and Word apps into the bargain.
The same challenges applied to my thirteen-inch Air running Mojave, but because of its 8GB memory I have been able to upgrade it to Monterey and it is now my go-to laptop for away-from-office activities. It runs Monterey quite happily with 8GB memory, and I persevere with the latest version of Pages, plus I installed a new copy of Word. And I’m back to using Apple Mail.
However, my eleven-inch Air would likely find anything beyond Mavericks too much for its 4GB memory. I love that smaller Air for its portability but due to its 4GB of memory it is now facing what amounts to retirement. Not early retirement, of course, since 2015 to 2023 is rather impressive. But had it had a memory upgrade at the point of purchase, it seems I would probably still be using it even now.
For the OP who, like me, tends to use Macs across an extended period, extra memory at the time of purchase can be additional insurance for securing an even longer-serving computer.
I did get a Mac Mini M2 Pro last year (rather than the M2), to secure the base 16 GB memory (plus larger SSD and extra ports). It should, with luck, last me until my own retirement! I’ll continue to run the thirteen-inch Air until Monterey begins to admit defeat.