Yeah, it's huge. I recently replaced the screen of a friend's ThinkPad as a favour. I was a tad anxious because I've not done a repair on this scale before, but I said yes because of how famously repairable ThinkPads are.

The screen repair was way more involved than the upgrade you describe, but it didn't take me more than half an hour, and that was me being extra cautious. The great thing about a laptop that's known for repairability is the abundance of documentation you can find online, it becomes a self reinforcing cycle after a certain point