Here are two plots of FinancialData plotted as a function of time:

If you want to compare the two plots, you can make a grid:

But the axes do not exactly line up, which makes it harder to make a useful comparison.

(Mathematica automatically draws the plot area as large as possible and gives only as much space to the axis labels as is necessary. Normally this is what you want, but not in this case.)

The solution is to set the padding for the plot manually with the ImagePadding option:

Now the axes on the plots line up:

You can also use ImagePadding to align plots in the horizontal as well as the vertical direction.