I suspect the detail of my records is exceeded on FTO only by Frank. Even though I have a "garbage can memory" after 30 years and 780 ski days you will forget stuff if you don't have some kind of records. There is some utility. For example, after the nice corn weekend of June 10-11 at Mammoth, I did wonder, "how often is it like that?" and due to the recordkeeping I could look it up.
Vertical is more important as long as you don't let "the tail wag the dog" and let it influence choice of terrain. Even though I did it for 17 years by keeping a running chairlift total in my head, it's much better with the altimeter watch when I only need to check a few times a day.
I have a hard time saying just days is a good measure. To use Patrick as an example do you really want to equate a couple of hours at a local Ottawa hill to the wire-to-wire powderfest at Jackson on January 29? Vertical + powder vertical is the best crude/simple measure of quality IMHO, both at the day and season level of measurement. Counting that Jackson day as 43K (31 + 12 powder) puts it in my top 10 lifetime, which is where I would also rank it subjectively.
I do have plenty of respect for the backcountry, earn-you-turns skiing, even though I've done only a little of that. It's logical to track that separately, as both river and I do. I have little doubt some people consider their best backcountry days among their best overall. But I would also contend that any day where vertical + powder is close to 40K would rank highly in anybody's book.
In an overall context I do have a good idea of the $ as well. For 10+ "family years" it was around $5-6K per year, which I hope is not an unrealistic budget for many skiing families. This covered around 60 ski days distributed (not equally) among 4 family members and was inclusive of things like equipment, travel/lodging cost and day care for kids when below skiing age. The "Warren Miller years" raised that budget 50% or so, and the last 2 years, unconstrained by a non-skiing ex-wife, are in a different league due to indulgences like Las Lenas and Mike Wiegele.