Some others here have more than adequately given explanation for the potential differences in battery life.

I would add that Apple's figures are likely to err on the conservative side and be based on a particular type of user and usage - which may or may not correspond with your situation.

In direct response to the question you ask about *which* MacBook you ought to keep, I would suggest that you consider how much continuous battery life you actually consume in sessions between which you have adequate opportunity for charging. So, do you really need more than 11 hours or whatever your type of work utilises?

Given that you have both machines, perhaps planning and performing your own comparison test of the two machines for precisely the same and typical tasks you might undertake and looking at the experience on each machine for factors such as:

* The *actual* battery usage to complete the tasks?

* Battery usage for various types of tasks?

* The total time taken to complete the tasks?

* How easy and satisfied you feel of the experience on each machine?

Ideally, you would also eliminate as many other factors as you can that may skew the results, i.e.

* Do the tests in as close to possible the same conditions and with the same state of mind and lack of other distractions, mental or physical

Of course, if you adopt this process, how rigorously you perform it will depend on how worthwhile you believe it to be, what time you have, how much you want a clear understanding of the difference in use of the two machines and probably other factors.

I offer the idea only as one practical way that you could gain some real-life and real-time information to inform your decision, rather than going with gut feeling or the particular bias or view of others.

Thank you for your posts. I find them interesting and enjoyable with, very often, food for thought.