I'm currently using a 13" early-2014 MacBook Air which seems to be serving my needs just fine, especially since I don't require it to do massive multimedia jobs or any such thing. But I know that 3 years can be a long time in today's world of ever-increasing memory/processing/security demands. How soon will I need to think about replacing this machine -- or is it already obsolete without my even realizing it? As you can probably tell, I don't keep up with technology very well. I ran a 2004 iBook for years and years until it was obviously both way too pokey and way too insecure to continue.