How often do you check your Amazon ranking/sales etc?

Our March 15th.

I was wondering how often anyone checks their Amazon sales figures or their all for ranking? When I first started publishing on Kindle I checked my sales everyday – I know that's ridiculous– but every time I sold a book in the early days I was thrilled.
After a few months I became less  frenetic and adopted the following system. Every Saturday morning I write down my sales the previous week, listing them according to type of book and royalty received, and then work out my weekly and daily income. I record this and store it. At the end of the year I have a record of exactly what sold best and when.
At the end of the month I total at sales for each individual book  and enter them in the back of my diary – I put in the estimated income and then adjust this up-or-down according to what I actually get paid three months later.
February last year was my worst month by 50% but this year I've sold more this month than I did in January of December . I know I have far more books available but it's still rather mystifying.
Unfortunately I forgot it was 1 March on Saturday and when I looked  my Amazon sales had vanished (as they always do on the first) and I've had to wait until today to try and work out what I sold last week.
When Amazon first introduced author ranking I was checking  far too often – now I only look when someone reminds me. I'm not selling as many books as I did a year ago but making more as the books that are selling have a higher royalty rate.  I don't really need to see a line heading downwards on a graph (as it did at the end of January) to know that my sales dipped drastically.
I do  check how sales are going by looking on the Amazon pages themselves – I love it when any of my books sneak into the top hundred of a list. (Four of them are at the moment.)
I've noticed that its harder to get into the top hundred on any list than it was last year – I think hundreds of thousands (possibly an exaggeration) of us are now publishing their blacklists, or new books, on Kindle instead of going with a traditional publisher.
I'm delighted to see that my new World War II family saga, Barbara's War – The Middle Years, is already selling well. I've done no publicity tool so these must be people who were waiting at the second in three books series to be published.
Would be interested to hear if anyone else wastes as much time as I do?