I think it might just be luck... Laptops are supposed to die earlier because they are carried/ battered around and due to cramped conditions, components tend to run much hotter in laptops than pcs resulting in a shorter life.
However, my laptops seem to last longer than my desktops too! Maybe it's because I fiddle around with/ upgrade my pc, but leave the laptops be...?
Saying that, my oldest laptop still works but has quite a few quirks now (it's 4-5 years old). For example, if you put the screen back more than 90 degrees it turns off and only 2 out of 4 usb portsd work anymore! Oh well.