I'm always happier using something I've taken apart and put back together. I do own a few devices I've been afraid to disassemble (I'm looking at you, iPhone!), and I'm working on changing that--I want to replace my own batteries and get better at troubleshooting older devices. I figure med students practice on cadavers, and that's my current approach to phones and tablets. It turns out my friends have a lot of dead and functionally obsolete Kindles and iPhones and iPads and Google phones gathering dust, so I'm doing a lot of zero-risk teardowns!
On the high-risk side, yesterday I pulled the heat sink and fans out of my work laptop, blew out dust and an impressive amount of dog hair, and re-pasted the heat sink. It's running more quietly now!