Dual/Triple Boot will not void the warranty. Apple provides the means to Dual Boot into Windows.
Adding RAM is a user upgrade. Check to see if your particular MacBook requires the RAM in each slot to be the same size and type.
There is some debate as to whether AppleCare will cover for an accidentally damaged MacBook. Sometimes it is and other times is does not appear to be. Check the fine print.
AppleCare appears to be only available out to three years. Contrary to what you believe now, you will still be using that MacBook after 3 years.
On the subject of Linux, I will bow to others for the answers.
P
I hope to soon acquire a Macbook with a 3 year AppleCare Protection Plan (APP). With the notebook, protection plan, and a backpack to carry it in, plus state taxes, the total comes to just under $1,300.
I was thinking of maybe doing a few things to the laptop, and I was wondering if any of them would void the warranty.
*Dual/triple boot - putting windows and/or linux on there
I do have a valid license for Windows, and I was wondering; does anyone know if Fedora linux will work on the Macbook? Its processor is Intel, so it should, right? Would drivers be difficult? Or, if not Fedora, what's the best distro for Macbooks, especially considering wireless (wifi & bluetooth)?
*Adding RAM - maybe another gig
I probably won't need any more RAM than a gig (my desktop PC only has 512, which I'm mostly happy with), but if I decide to upgrade, and go with a third party set of RAM, will that void my warranty?
*Accidental breakage - is it covered?
If I accidentally drop the notebook, will the APP cover it? Or does it only cover defects?
If I feel that the laptop still has use after three years (which, with today's technology moving at its rate, I'd say probably not), could I purchase additional years of the APP?

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