If you are consistently running out of data you need to be a little more proactive in determining just where on the "usage curve" you are.
With 15 GB per month you can only allow 3.75 GB per week.
The download Status Meter has a quick method to determine just where you are at any given point:
If you find yourself running "behind" you can reduce the number of devices you have connected or take other measures to reduce your rate of usage or determine where the data leak is.
With a capped service you have to learn to pace yourself.
To be fairly honest, a MAC is nothing more than a generic PC, nothing notably different as far as browsing the internet.
Right. And sure, a Windows PC tends to have everything enabled/turned on from the get go, but it's like going into a house that has everything electrical turned on (kids...go figure). If you take a little time to go around and turn things off that you don't need, you are going to save a lot on your electric bill.
No one has to watch on demand films. No one has to watch on demand TV shows. No one has to watch dozens of goofy animal videos every day on YouTube and Facebook. It seems, though, that not only can some people simply not function without these things, they believe that all ISPs should provide the bandwidth for such, no matter what. I mean, what is this, the STONE AGE? LOL.