I have been considering the economics of hanging on to laptops for longer than one or two years, for my White MB is 18 months old, and with new updates aplenty in that period, always depreciating in price. If I sell the MB and buy the 13" MBP the difference to pay would be around £250. The £250 loss in 18 mths equates to spending £1000 every 6 years on a laptop. That is so very reasonable that everyone should be doing it and nobody hanging on to laptops for much longer: - in those 6 years I will have had 4 laptops not just one; - I will be keeping up to date with technologies such as built-in SD card slot and whatever else changes inside, outside and on the side of Apple machines; - the excitement of 4 laptops in 6 years in far greater than one ageing tank; and; - the self-satisfaction is immense! So much so that I'm posting a new thread with this comment to invite thoughts. EDIT: to acknowledge that many are already doing and I wasn't the first human to think of it.