Just about to get my new iMac and considering doing a clean install. I have not done a clean install since my first mac back in 2009...so I figure there is probably a lot of schmutz on my mac. Suggestions for doing this efficiently? Would you use some of migration assistant, but not all? I am most concerned bringing over mail (as contacts should sync with iCloud). Any other issues with doing a clean install from people who have done it before with a new mac? I imagine apps cannot be transferred over (Unless I use migration assistant) and I will need to re-download?