I woke up this morning with the idea of planning what inventory of pipe tobacco I would need to cover my smoke habits for some years ahead. However, I found some estimation problems along the way. For instance, How many average bowls can I get from a tin of say 50gr? What would the cost of an average pipe tobacco tin would be?

I am guessing that if you can get like 10 pipe loads from an 50 gr tin, If smoke just one bowl every day I would need 36.5 tins for a year of pipe consumption. If the average price of high quality is $20, then I would need to spend like $730 for a year of pipe tobacco inventory. Assuming I would appreciate to smoke well aged tobacco and have three years of reserves, rather than "just in time" stock, I would need to invest $2190 to have enough reserves for three years. Then I would need to spend $730 every year to keep always at least 2 years of pipe tobacco of inventory.

Do you have any experiences to share about budgeting you future pipe tobacco expenditures? Are the assumptions I made accurate?

I pretty much do the same calculation though my assumptions are a bit different.

I assume 10 bowls per ounce of tobacco (based on tobaccocellar.org's estimate)= 17.5 bowls per 50g tin.
I assume $10 a tin (50g) on average (based on the type of tobacco I smoke and smokingpipes.com's prices).

Since I smoke 1 bowl/day on average, my annual budget would be:

1x (365/17.5) x $10 = $209

Have you considered buying bulk? Even at 60$ a pound you would cut your budget in almost half.

I have been buying bulk for the majority of my "regular" smoking and tins for just evenings. It stretches my money quite a bit and allows for a good amount to cellar.

Maybe not what your asking, but I thought I'd through it out there...

I think you're on the right track. A mix of tinned and bulk tobaccos make up my normal purchases. And then, there are the 'scores' that one stumbles upon now and then...like the pounder of C&D Night Train over on Smoking Pipes in the tinned section for under thirty bucks!

The one thing that you didn't take into account was the occasional but regular "wild ass" purchases when you just kinda go nuts and HAVE TO HAVE some special or new thing. Happens to me all the time! lol

You have to take into account that tobacco will never be any cheaper than it is today. So you should buy now as much as you can afford. You'll be building a cellar and not have to buy as much later as the prices increase over the years.

My spending will certainly drop this year.
I nearly have "enough."

Do you budget all your expenses on a yearly basis?
At our home, we go monthly and I set my pipe expenditures along with the rest. Too many things go in and out of stock throughout the year for me to think on that scale. I used to do it that way when I quit cigarettes.
My cigarette costs were about $175 a month in the state of Georgia. Thus I set aside about $100 a month to stock and smoke my pipe tobacco. Sometimes I use the whole $100; many times I do not. This way I'm spending less than I was to do something I enjoy a hell of a lot more.
Unless you only get paid once or twice a year, I would consider a different budget- Otherwise it's hard to to track how well you are staying on budget.
If you are an expense nut like myself, keep track of of your total tobacco expenses over the years and average them out. That's me though. I like to play with numbers and set weird goals.
One month buy bulk. Record how much is left at the end.
The next, buy tins. Do the same at the end.
Play around and try to get the most enjoyment for your buck, but don't drive yourself crazy.
This is after all a way to relax.