My problem seems like it must be a very common one, so I presume Excel has a
built in solution that I haven't stumbled upon.

Basically I frequently plot XY charts where the X axis contains dates. And to
make the chart look right I will want the date labels to occur at Jan 1 of each
year. So I start the chart from Jan 1 of some year, and tell it to make the
grids on 365.25 day intervals. The result is that some of my X axis labels will
be Jan 1 but some will be Dec 31.

The only solution I've found that works mostly is to sit and tweak the start
date of the chart to be some number of hours beyond Jan 01 until the grids fall
on the proper dates. It's not a fool proof solution and I assume this issue is
common enough that Excel builds in a solution of some kind when using dates like
this.

Any inspiration? Thanks.

Bill