I use 2 separate approaches to manage my photos. First of all, I enable photostream on my iPhone and on my Mac. This gets photos copied to my Mac automagically. About once a month, I open iPhoto and look around to make sure the automatically created events such as "January 2014 Photostream" are showing up. Then I move on to my second method...
I have an external HDD with a folder named "photos". In iPhoto, I select everything in one of those Photostream events and drag them all to Finder to a folder I created just for that month. This gives me 2 copies, one in iPhoto and one in Finder.
Then there is a third thing I do. Every now and then I connect my iPhone via a USB cable and use Image Capture to transfer and delete photos from the camera roll. This saves me time versus deleting them on the phone after they have showed up in Photostream. It also allows me to copy videos which are not transferred by Photostream. It's not uncommon for me to have 3 or more Gig of photos and videos on my phone so I'll do the image transfer thing about every 90 days or so. I have OSX set to "do nothing" when I connect my phone because I prefer to manage things myself.