The longest I've ever had a Mac was six years, when I used a Mac Plus from 1989-1995, when I got my dads old IIsi. Then in 1996 I bought a Quadra 605, and in 1998 I bought a PowerMac 7200, and in 2000 I bought a new iMac. In 2001 I bought a Powerbook Lombard 400, and in 2002 I bought a G4/466. Then in 2003 I bought a new Powerbook 12" 1ghz, and that worked perfectly for me for three years until December 2006 when I bought a new Macbook which needed a new motherboard six months later. Since then it's worked pretty OK though it does seem to completely lock up every now and then requiring a forced shutdown, which didn't happen with the old Powerbook 12" if I recall correctly. Our 4 year old Dell PC has worked perfectly and we will continue to use it until it blows up.