I have a mid 2010 13" MBP that is in needs to be upgraded. The main issues are that the battery is dead, and the computer is quite sluggish. When purchased, it was the basic model, 4 gigs ram, 2.66 Core 2 processor - honestly not that special of a machine. a So here's my conundrum, do I upgrade? Swap out the battery, up the ram to 8 gigs and put in a SSD, or do I buy a new MBP (probably a refurb'ed). What it boils down to is, I wonder if it is even worth it to upgrade my current MBP? Would I see an significant improvement in performance for my current MBP if I do upgrade it? Would this improvement last? Realistically speaking, how much additional time would upgrading buy me for my MBP?