Well, I have this laptop and clean the fan every other month with air...
...I'm 100% certain that it wouldn't have lasted for the 6 years it already has if I didn't.
IMO the most important thing about opening one is that it's easy to do so, for example the Sony VAIO laptops are a fucking pain in the ass to open because you have to disassemble the entire thing in a million steps and keep track of lots of screws...
I got lucky that I have to unscrew like 4 screws and can be done with it in 5 minutes. So in my case it's certainly worth it.
In the end it's up to you what you'll do, also depends on what you want to fix and as I said the difficulty of it all. I would also never touch the inner parts of the thing with my bare hands because you can never know if you get zapped and end in a casket.