I'm sure you've answered this time and time again but I need some advice. I've had a mid 2010 15" with hi-res anti-glare screen for four years now and it's become quite hit and miss. Some days it's fine, although understandably slower after four years of daily use, but sometimes it's really, really slow, can't handle more than five apps at a time and freezes (especially iTunes, Mail and Safari) until I force quit them. When it has one of its episodes, the fan is also really loud like it wants to take off into space. I mainly use it for Internet, Mail, iTunes, word processing, photos, downloads, the occasional game. I run no strenuous programmes but I do use it a lot; 10 hours on average daily. I want the highest spec 15" retina as I assume that would last me another 4/5+ years, and longer than say the 13" lower spec model. Do you think it's worth upgrading now before it gets much worse? Does it sound like it would last another year? And with the new machines out this week, I can either get one for £1839 with discount through my work or £1599 for the 2013 model from the refurb store. Is it worth extra £200+ for the newer model? Thanks for any help.