I have been building with Lego since I was 2 (I am now 23) and I have never used the instructions to build a set until last week (Dwarven Mine) and only did that because my roommates wanted to help. My confession:
Every Set I buy, I have to build from the pictures on the box ONLY (No Instructions).
Once I have done this. I usually take the set apart fully - take the pieces I want for my current projects, and put the rest into their respective color bin for use at a later date.