Correction!
lobster
Crusty Veteran
As we know Do we assume doing the same will lead to improvement? Of course not. Many of us act that way [lobster raises guilty claw] ... 
It is only by overcoming useless or counter productive emotional, mental and behavoural loops that the condititions of Nirvana come into play. Obvious? I think so too.
This is something we have to realise, internalise and act on. Obvious? I certainly hope so.
This understanding was for me the basis of any minimal progress made. Oh I still chop wood (mostly my own head) and carry water (mostly my own tears of reality) but nonetheless I know which direction realisation requires ... and it ain't more of the same ...
http://lifehacker.com/four-confusing-zen-quotes-and-what-you-can-learn-from-1676177538
What's new?
Comments
The MOMENT ......
OK, first of all, is that really the definition of insanity? I doubt it actually.
And secondly, people (and other sentient beings) do what works. We keep trying unrelentingly because we have learned that it does sometimes lead to success. It doesn't have to lead to success every single time to work as an effective motivator, it just has to work often enough to reinforce the behavior.
If at first you don't succeed . . .
I think both of you're right and it depends on how you look at it (IMO)
I think @lobster meant that if you are not being successful at something (i.e. concentration during meditation) to try something new because maybe there is a reason for it (i.e. get new music or set up a little meditation area or chant a new mantra).
And, if I am correct @Steve_B is saying that maybe there isn't anything wrong with what you are doing but you need more practice at it or dicsipline since not everything comes right away. So, it all depends on what it is and what you have already done.
That's my thought
Who knows yourself better than you? I would hope the answer is no one.
With that being said, I think that it is worth mentioning that what works for one person, does not always work for another.
For me I am not sure if it is persistence or stubbornness that tends to make me want to carry on with something that may not be producing the desired results.
Tee hee!
Strange as it may seem a genuine teacher will know you better than yourself. Not the ego and monkey mind, which is the gibbering but the genuine Buddha Nature, which is in her nature to nurture ...
An archivist, librarian or monk exemplar can certainly provide part of the package BUT to be empowered into the unborn/nirvana/eureka moment, what is required? This is precisely why I am so harsh on egoists, false gurus and unrealised 'teachers'.
Yes we need a healthy, grounded ego for most things and Buddhism is no different. It is not correct to go la-la or ga-ga and pretend this is a spiritual path. Within our karma, circumstances and degree of madness, we need to correct our ... well everything we can ... not what we can't ...
Iz plan?