In article , Rob
wrote:

i recently opened one of my laptops to swap a hard drive and there was
no dust or gunk. it's 4 years old, which is plenty of time for that to
happen.

You can't see where the dust actually collects when you change the HDD.

oh yes i can. for my laptop, the top panel (including the keyboard)
comes off and the entire internals are exposed, including the fans. if
there was any dust accumulation, it would be very visible.