I bought my first Apple, an iMac, 2005. It died in 2008. My current model still works but much slower, especially on iTunes and Microsoft Word both of which give me the "spinning wheel of slowness" evidencing a moribund computer. Restarting doesn't seem to help.
My wife's Apple laptop, acquired from KCRW in a contest drawing we won in 2004, died in 3 years. Her first iMac died in 3 years. Her second one has slowed down.
One of my students has an Apple and he says it gets slower and slower. He added that all his friends who have Apples that suffer the same decline.
Moreover, when we went to the Apple Store in Manhattan Beach to see if we could salvage my dead Apple a couple of years back, a candid employee at the regrettably named "Genius Bar" told us in his experience the computers die within 3 years and explained that they are NOT made of solid state parts.
When my current model dies, I'm seriously considering getting a PC. On the other hand, what if a PC has a shelf life of 3 years as well?
The most compelling reason I stick to Apple is that hackers program most of their ill will for PCs so I'm in a bit of a dilemma.