I bought a Macbook Unibody back in October 2008 and have since upgraded its memory from 2 x 1GB to 2 x 2GB and eventually 2 x 4GB. That, as well as an SSD disk have made my Macbook an enjoyable machine for 5 years. The battery, however, is completely useless (despite a replacement two years ago) and the core 2 duo 2.0 processor is starting to get difficulties as well. The fan is spinning pretty much all the time and I now need to keep it on 24/7 as it boots with a black screen 9 out of 10 times. I could try to have it repaired, but sooner or later I'll be forced to buy a new machine. Since I intend to keep the new machine for another 3-4 years, I want to know if 8GB would suffice for that time period or is it likely that within 1-2 years 8GB will be the bare minimum to keep apps and OS X running smoothly? I could go for 16gb, but I can get 10% discount on the standard models, which is the reason behind my question.