Not all that it’s all that unusual to see given all the replies to this thread but I’m also still running a late 2008 aluminum unibody 2.4 ghz Macbook. (5,1?) Bought early spring of 2009
I replaced the battery last year (clearly didn’t need it since I saw no real improvement) a 250 gig OWC SSD a few years ago, bumped up the ram to 6 gig initially, (4 and 2 in the two slots...yes at will do it) then to 8 (4 and 4) with the install of the SSD. When the SSD went in I went to Yosemite, but I believe it can hack El Capitan. I just can’t be bothered to go through the hassle. It remains pretty much bulletproof. It would have to die for me to replace it. S
MacBook5,1 is indeed the 2008 aluminum MacBook.
BTW, I'm noticing that my MacBook5,1 Core 2 Duo 2.0 GHz 8 GB with SSD is feeling more noticeably slower these days compared to my MacBookPro5,5 Core 2 Duo 2.26 GHz 8 GB with SSD.
The two machines are nearly identical in specs on paper, aside from the 13% CPU speed advantage of the MBP5,5, but I think some of the difference I'm noticing is related to the SSD. The one in the MB5,1 is the first SSD I ever bought. It was one with a Toshiba controller that Apple also used back in the day when it didn't do TRIM. It did hardcore garbage collection instead, but unfortunately was slow for an SSD, even for its time. In contrast, the MBP5,5 has a Samsung 840 EVO in it, which feels considerably faster. (I was able to compare the two drives in the same MBP5,5.)
So, despite both having SSD, even with these old machines, having a faster SSD can help, up to a certain point anyway.
In any case, both are otherwise quite decent running 10.13 High Sierra. Note that 10.13.6 High Sierra supports AirPlay 2. 10.13 also has the best version of Photos.
However, my preferred Mac laptop is my 2017 12" MacBook Core m3-7Y32. It feels way, way faster than both of those, and that's what I'm typing on now. It's my main travel machine, since it's only 2 lbs and takes up such little space in my briefcase. The other bonus is that I can often travel just with a single iPad USB charger to charge both my MacBook and my iPhone. I just have to carry one USB-A to Lightning cable and one USB-A to USB-C cable.(I'd carry the MacBook's USB-C charger which will charge the MacBook faster, but I currently don't have a USB-C to Lightning cable yet.)