I upgraded my MacBook Pro 2012 to 16GB RAM and used OCLP to bring it up to macOS Monterey 12.7.6. I'm astounded this computer is 14 years old! It's a wonderful machine. I have been using it daily since I acquired it - albeit with only 4GB RAM, fortunately it came with a 250GB SSD. I have been using it for Youtube, Music, Movies, and even some 'almost-classic' (?) gaming! I've been playing Civ V on this and at turn 123 it's still running just fine on a medium map - I'm impressed! I've been using Apple Notes extensively, have a bunch of other games installed via Steam as well. I am loving this machine!
I am downloading Half Life 2 via the internets "free rental" system despite owning all the Half Life games on Steam, because for whatever reason that is not shown as an option on Steam - a bit annoyed by that.
My 2008 MacBook Pro I acquired 8GB RAM and a 8GB RAM from Aliexpress and installed Windows 7 on it - I'm turning that into a sort of retro gaming machine for Windows games from roughly 1998 ~ 2008. So far I've only tested out Farcry and Sim City 4 Deluxe on it - but its great! And the 15 inch screen really shines there. I'm hoping to set it up in a permanent spot somewhere as a sort of "Hey, here's a nice 15" Macbook ready and waiting to be played". I love it also!
I also attempted to repair my 2009 Macbook Pro I bought as 'broken' from eBay. Opened it, cleaned it with Elektro and Compressed Air, replaced the RAM (Also 8GB), kept the original HDD... Sadly, one of the dim slots or the clip is busted, needs work. But works with 4GB RAM for now. Considering making this a Windows XP machine. I acquired a second Macbook Pro 2009 with no peripherals hoping to use it for parts - No luck - The exact same broken dim slot or clip issue! Testing with various RAM sticks, verified its the DIMM slot. So that's a project with a bit of work ahead of me.
I am having a blast with these computers!