There is no way to AVOID it, though mine has never done it.  Keep it well vented, and cleaned!  Do not enclose the unit behind any kind of doors, even GLASS.  That also means, the rear should be open as well, so you are not circulating exhaust on a shelf.   Mine only failed because the DVD drive did, none of my consoles over 3-light of death on me.

My kids have one, theirs goes back today for 3-LOD, but theirs is in an ENCLOSED space, and I told them not to do that, they insisted, and a year later, boom...  Open front, but the back is closed, on a shelf, so, they were warned. 

You got to remember, you basically have a 33% chance of getting the 3-LOD, yeah, horrible odds for  technology these days...   Unless you can get a Jasper version (wait till December 08), you run that risk, even with the Zypher, and Falcon versions...   Jasper will have 65nm chips, the next one will have a unified CHIP with both the CPU/GPU on it, and possibly using 45nm technology, that being the Valhalla version.