A spin off question off MrsJYW's thread about MacBooks... She posted that MBs should last a "long time", but why would a MacBook last longer than a PC laptop?

Is it because of build quality or software or something else? I'm curious because I used my previous laptop for 5 years before I decided to buy a new one and DH has used his current laptop going on 5 years. We both use our laptops daily.

Are MacBooks reputed to last much longer than that? I have a MacBook Air and since the battery is integrated and once the battery dies, depending on the replacement cost, I might have to get a new machine.