I haven't been timing flights, but my sense is I get perhaps 2 more minutes out of the higher capacity batteries. It is true that removing camera and prop guards extend the time some as well...perhaps a minute or so?
Caveat: I'm a rookie with quads, but many years ago was an intermediate+ level RC glider pilot, and a "barely air safe" RC heli pilot. Take the following with the appropriate grain of salt:
If you are just learning, you may find that flight time is less important
right now than you might think. Your first flights should be about learning basics: stable hover, forward and back to you, side to side, in and out of hover. Fly box patterns and circles and S's with the head of the quad facing away from you. Then experiment with flying "sideways" to you and translating the stick movements. The next stage is practicing flying toward you - it takes practice and training your brain. "Headless" mode is fine, but I strongly recommend you don't learn that way - do it by the numbers.
In the learning stages, mental fatigue will set in quickly. Short flights are your friend. Also, you will get to the point where you start to get confused about orientation and control. When that happens, try to hover the quad, get the nose oriented away from you, and go back to some basic moves until you are back in firm control. Anyone who pulls one out of the box thinking that in 15 minutes they are going to be punching holes in the sky is about to lose or destroy their new toy. The good news is that if you talk to anyone who flew (or tried to learn to fly) a classic RC heli without counter-rotating props, the learning curve on a quad is about 1/100th as long (and that may not be an exaggeration).
More experienced quad flyers can add a ton of insights to the above, I'm sure.
