Why does my internet keep disconnecting on my mac?

Question

I bought a new mac this christmas, and so far the internet has been repeatedly disconnecting until I turn the wifi off and back on. I was okay the first time this happened but now it has been months. Its getting VERY annoying. How can I fix this?
(My mac is a Macbook Pro OS X Yosemite.)

Answer 1

How to check if there are other WiFi base stations near by
Option-Click on the WiFi icon in your menu bar -> select Open Wireless Diagnostics
Enter your Admin password when prompted.
Wireless Diagnostics -> Windows -> Utilities -> Wi-Fi Scan tab
Click [Scan Now] button in the lower right corner.
You may want to grow the window to see all the columns
The WiFi base station and channel your Mac is using will be "Bold" and all the other WiFi signals will be normal type.
You are interested in the RSSI column and the Noise column
The smaller negative value the stronger signal.  -37 is the strong signal in my house.  My nearest neighbor is -77.  In an appartment/condo complex you may have signals as strong or stronger than your signal.
The Noise signal should be a large negative value. -88 to -90's indicates a very small amount of noise.  Noise is an indication of interference.  A large negative value indicates very little noise.
Channels should not overlap.  The 2.4GHz channels should be 5 channels apart.  1, 6, and 11 are the preferred channels in countries that allow 1-11.  Some countries allow 1-13.  So you want to look for in use channels with a small negative RSSI values that are less than 5 channels away from your 2.4GHz channel.
The 5GHz channels are assigned without any overlap, so they should not be a problem.
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Change of subject
Sometimes Bluetooth interferes with the 2.4GHz WiFi.  If you are using Bluetooth devices, try turning off Bluetooth on your Mac.  This is an experiment.
Microwave ovens use 2.4GHz.  If your computer or your WiFi base station is picking up microwave oven leaking, then that can cause interference (the Noise above).  The reason WIFi is allowed to use the 2.4GHz frequencies is because that band if fill with too many interfering signals, such as Microwave ovens.
2.4GHz cordless phones.  Yours or ones owned by your neighbors (assuming your neighbors are nearby, such as row homes, apartments, condos, etc... can interfere with 2.4GHz WiFi
2.4GHz baby monitors are worse than 2.4GHz cordless phones, because baby monitors run all the time.  So if you are using, or a nearby neighbor is using a 2.4GHz baby monitor, that could be a problem.
Buildings with metal framing.  Concrete with rebar, or some builders use metal studs.  These can block WiFi signals.