Besides, when I pay a premium price for a product I expect it to be useful for more than a couple of years.
I was specifically replying to this comment:
> Why is hardware upgradeability so important? What's the harm in just upgrading to the next device?
Not everybody has the money to buy the next device, so upgrading is a great option to get a couple more years of work from a little old but otherwise solid laptop.
But, whatever the reason, Apple hardware tend to hold on to its value longer, without doubt.
I recently sold my 2010 13' Macbook Air, dented and with a cracked screen a for 300$ on ebay (and I expected more based on similar auctions), about 1/4 the price of a new model for a broken 4.5 years old model.
Technically you could just upgrade every year and recoup at least 60%-70% of the original price.