"Work will expand to fill the time allowed," was one of those Laws that were popular a while ago.
So applying that to solar, we see that the more you have the more you use.
It is true that you find out what the balance is for YOU by experience.
No application to anyone else, but the first year (2011) we got solar I had five batteries and got 80w of solar. A month later we had 210w solar. That proved to be too much, so I returned the 80w and kept the 130w panel in 2011.
In 2012 we ran with just the 130w panel (but now on four batteries), but had it in a contraption for tilting/twirling and did just fine.
However late in 2012 panel prices fell and I couldn't resist! So I got the idea I could get more solar and not have a contraption and come out the same or better. So I got two more panels real cheap.
Then in winter I got bored and built another type of contraption for the two new panels. Now here we are in 2013, camping with vastly more solar than we need, and are looking for more things to do to eat up battery AH to justify all this solar!
Who is running this whole thing anyway? Me or the solar monster? At least I don't have MPPT!!! (That would be a complete surrender to the solar monster!)