The depreciation on Apple laptops is low enough that you can resell it and trade up to the latest refresh once a year for the same cost as trading up once every 3 years. If you're interested in the best bang-for-your-buck and can put up with the hassle, you should definitely think about it.
Thinking a macbook pro with SSD & 8GB has a chance of lasting even longer.
The point is more that rather than running one machine into the ground until it's thoroughly obsolete (three years give or take) and then paying full price for a new one, one could resell a year later when it's still worth nearly what you paid for it and upgrade to the newest model. The price per year works out to be more or less the same, but you have cutting-edge hardware year after year rather than spending two years out of three in comparative obsolescence.
The only thing I use my DVD drive for is movies (but I recently got Netflix), and a recent troubleshooting round on a 1st gen MBA. And I made an install USB stick, so I don't need the drive any more anyway.
This has easily been the longest-lasting computer I've purchased, especially in the laptop realm. I'm thrilled with what it cost me.
I owned my white, 1st-generation MacBook for 5 years. To be fair, I wasn't coding then, so I might take your advice for this new laptop.