How much tobacco do I need?

Slots? Yes, it's a unit of tobacco; not well known, in fact not known beyond my cellar, until now.
I'm not particularly happy with the name but that's how I think of it. The problem with all the other measures is that they don't relate directly to bowls.

One Slot is 40 bowls. That's equivalent to the number of bowls from a 4 oz tin of tobacco, so a 2oz tin of GLP's is 1/2 of a Slot.

10 lb (eg your cellar) is 40 Slots - that's 1600 bowls. It's direct and useful at a glance. It's a useful capacity measure that relates more directly to smokes. It's very easy to take any pound measurement and divide it by ten and then multiply the result by 40. If somebody says he has a 50 lb cellar than we can immediately conclude that he has 200 Slots (50/10 = 5, and 5*40=200) or 8000 bowls in the cellar. Even if he has an odd amount it's fairly easy eg a 111 lb cellar is (111/10=11.1, and 11.1*40= ) 444 slots.

Why is a Slot so useful? If one smokes about one bowl per day then there are 9 Slots to a year (9 * 40 = 360). If you smoke two bowls per day then 18 Slots make up your year. In fact it's convenient to see a year as a table 9 slots wide by the number bowls per day in height.

A year for a 3 bowl per day man can be represented as:

Bowl 1: Slot 1, Slot 2, Slot 3,....., Slot 9
Bowl 2: Slot 1, Slot 2, Slot 3,....., Slot 9
Bowl 3: Slot 1, Slot 2, Slot 3,....., Slot 9

That's 3 times 9 slots/year = 27 Slots. Don't always smoke 3 bowls per day? Fine, back it off some. I smoke about 24 Slots per year. I usually smoke two bowls per day and almost 50% of the time I will have a third.

If one has variety in the cellar then one can loosely interpret a single Slot as a 40 bowl 'visit' with a specific blend during the year. In that case the capacity of a cellared blend measured in Slots corresponds directly to the number of years that the owner can enjoy that cellared blend. So if I have 20 Slots of a particular blend then I know that it'll also last me about 20 years. Yes, 20 slots is 5 lbs but seeing it as twenty visits (the number of years that I could smoke 40 bowls each year) is a more direct measure of the cellar capacity for that single blend.

I think the Slot is a useful measure.

I think that a very useful first target for a modest cellar is to acquire 10 Slots of each of your top ten favourite blends. Ten Slots is 2.5 lbs times 10 blends is 25 lb. That's five 8 oz tins, or twenty 2 oz tins, or ten to twelve 100g tins, or 20-23 50g tins per favourite. Anything less and you haven't got enough and you're not done. It's easy to gather tinned blends in one-sies and two-sies. It's easy to believe that tinned blends in quantities of ones and twos is part the cellar when they're really incidental to the cellar. They're just one time treats, samples, things on the waiting list to try etc. Worthwhile to have but don't mistake them for the cellar. The cellar consists of the blends that you're trying to enjoy for a decade or more. This is actually harder than you might think. It's very easy to get distracted and never do it.

After that first target is met either build the same ten blends up beyond ten slots or identify another ten and do it again. I've found that it's very easy to identify ten to thirty blends - harder to fill them out though. I also want variety so I've picked blends or combinations of blends that represent a style that I want to preserve. The Burley slices are a good example and I've got Wessex, Solani, and Edgeworth such that, together, they are a cellared blend of more than 10 slots.