Years ago, I used to do something slightly crazy, that might or might not be possible still. Rather than my iMac being an external display for my MacBook Air, I

Years ago, I used to do something slightly crazy, that might or might not be possible still. Rather than my iMac being an external display for my MacBook Air, I put that one in Target Disk mode (over TB1) and booted the iMac from it. Still everything in one place, but actually leveraging the better specs. I believe it was Snow Leopard at the time, which had few issues doing so. While it worked surprisingly well, the main downside was I always had to shutdown to unplug. After about a year of working like that, my iMac got those notorious black spots, and shortly after, the first MacBook Pro retina came out (good times). Since then, I'm back to having a powerful laptop and an external display.