I've been using the MacBook Air since 2008 which shares many of the same design choices. It hasn't been an issue at all. The resale value of Apple computers has

I've been using the MacBook Air since 2008 which shares many of the same design choices. It hasn't been an issue at all. The resale value of Apple computers has to be considered too. If I can resell my old machine for 50-60% of it's original list price then upgrade-by-replacement is a good strategy. I only paid about $300 to upgrade from the 2008 MBA to the late 2012 MBA.