My macbook shuts off randomly, how do I know what's causing this and prevent it from happening again?

Question

My macbook shuts off and I kept a journal for it because mine's got complications.
July 1, 2014 (Tuesday)
I spilled a cup of choclate milk on my keyboard, it was soaked! But my battery was drained so I know nothing had short out. So I turned it over and never tried to turn it on.
July 2
I went to the nearest apple center and asked them to clean it for me. (I knew it wasn't a good idea to clean it myself) They put it in a plastic bag but I asked them to open it as soon as possible so I know what parts are affected. They told me they'd take a picture of the inside for me and go back after an hour. Milk was still inside everywhere so I asked them to take it in.
July 8
I called to get an update on my mac and they said it wasn't economically practical to repair it because they recommended a full system replacement. I got depressed and accepted my Mac's fate. But what's annoying is I put my mac in on July 2 and they only tried to clean it in July 5 which makes me think that was the reason my mac was irreparable.
July 9
I took my mac and tried to find another opinion but I showed the diagnostics from the apple store and they said they couldn't fix it. My parents were getting ready to buy a new one.
July 13
I realized that my mac didn't have charge when milk spilled on it so I tried to charge it and BOOM IT OPENED. They keyboards were sticky and it takes a moment before my computer reacts to the trackpad but it works! Even all the keys works! But it doesn't charge.
After lunch, it was workingp perfectly and my batteries were at 30% charge! I was really happy!
(in the interval my mac works perfectly, it stays for normal 7 hours when battery is charged fully)
However at July 19
There was no electricity for four days (A typhoon came in the Philippines) and my battery is about 7% so I went to the public market to get it charge while I wait for electricity. I charged it for about 3 hours and sideways because it was inside my backpack while it charged so noone will notice it. When I got home and opened my laptop, it shut off randomly after my desktop appeared after start up. So I was sad.
July 20
I found a solution online to use the option-shift-power button my mac opened and worked normally!
July 21
My computer was normal in the morning then in the afternoon it shut off again after I waked it up from sleep. Tried option-shift for about 3-5 times before it worked with varying intervals from 5-20 minutes each
July 22
I get nervous when I use it but it worked perfectly I was even able to edit with Final-cut pro and HD clips.
Wednesday
Worked perfectly in the morning but in the afternoon, after waking it up from sleep it won't turn on tried the option-shift then I tried resetting the SMC for about three times (my mac is a unibody) but it didn't turn on the whole evening.
Today Thursday morning July 24
I tried to reset SMC first thing in the morning after the thing won't turn on. After about an hour, I tried to turn my mac on normally and it opened. So what I did is to back up all my files. (It took the whole afternoon) and at night I ran diagnostics (D during start up) and no threats were found
Haven't been experiencing the trouble, as of the moment I'm writing this Jul 25, Friday (12:13 AM) HK time Philippines.
So what I'm asking here is what do I do to make sure this doesn't occur anymore. I probably written a very detailed log. So what else (diagnostics and other) should I do to prevent this from happening again. School starts in August and I will need my laptop to work perfectly to let me go through college with less burden. Thank you and I hope you reply. Any more questions about details on my Mac will be answered
Macbook Pro 13-inch, Mid 2012
Bought in December 2012
Processor  2.5 GHz Intel Core i5
Memory  4 GB 1600 MHz DDR3
Graphics  Intel HD Graphics 4000
Software  OS X 10.9.4 (13E28)

Answer 1

tryshdanielle wrote:
So what I'm asking here is what do I do to make sure this doesn't occur anymore.
Get a new computer. Consider switching to regular milk, or even a light fruit juice.