True Cost of Ownership

I count the number of shaves I get per soap/shave sample etc. I even have 3D graphs of soap/no of shave/brush and other relevant variables. I don't really do this to actually figure out which is costlier/cheaper. I just do it cause I love playing with numbers: I even know the average number of steps it takes for me to reach Office from train station: during each season . May be one day I will post my findings.

I have a few soaps that I have tick sheets on. I tend to be a little tight with my money so I was originally interested in finding out which soaps gave me the best bang for the buck (assuming I found their performance satisfactory).  I started that early on before I knew just how long it takes to use up soap.
I do not purposely overload my brush for the sake of using my soaps faster.  I have a water softener and have been using synthetic brushes for almost a year.  

Now I almost wish for smaller soaps so I can try more scents and makers.

Example:  I know soaps like MdC are known for being long lasting but it does not appeal to me on three levels. No offense to MdC soap lovers.  

1) The scents don't appeal to me, maybe I would like them but don't feel like spending the money to find out.
2) With all the options out there I don't want a soap to last me 200-300 shaves. Even though I am 3 years into this I still want to explore different options.
3) While the cost per shave might be lower the up front cost gets you only one scent where I would rather get 4-6 soaps for the same money and experience different makers and/or different scents.

I know this does not answer your question its just where I am at currently in this hobby.

I've been tracking since I started. The problem is that it has changed significantly over the past couple of years as my technique has adjusted, lathering skill has improved, and I've shifted over to synthetics. Now I just estimate passes / oz based on soap type (tallow, triple milled, vegan, m&P base).

OK, so I'm getting the vibe that most people will complain about the high cost of hardware, which in general is buy once and done, but don't seem to care about the cost of software, something one consumes and buys over and over again. Interesting. Its like complaining about the high cost of a car you keep for 10 years, but not caring that the price of tires might be $50 each or $500 each yet you will keep buying tires over and over again. OK, interesting.

"Buy cheap twice, quality once" and " If you have to ask you can't afford it." I have a modest, but high priced collection of classic pattern and use ties made by a freind in Thailand. If I broke down the cost X times worn and received compliments VS the polyester ties of my brother I saved money. Ditto with scents. I ALWAYS garner a compliment with Penhaligons.
Did I mention saving for a 1938 Phantom II Rolls Royce Sedanca DeVille?

It's not like comparing the cost of a set of $50 tires to a set of $500 tires. It's more like comparing the cost of a $25 regular oil change vs. a $45 synthetic oil change. Most (but not all) will agree that the added protection and performance is worth the extra cost.

I keep track of how many times I have used each soap, but don't worry about cost per shave since I have a healthy amount of soaps to choose from. Variety is the spice of life, and most soaps seem to last a very long time, but there are so many variables that one person may get 30 shaves from a tub of RR for example, while someone else may get 100 shaves from the same tub.