Conservation of tins of paint

We recently moved house and found that we have acquired a lot of tins of paint. I have worked out why.

When you have some painting to do, there are two possible sources of paint. Either you buy some new paint, or you try to use up some paint that you already own.

Obviously if you buy new paint then you're adding to your collection of tins of paint. But it is folly to think that using up existing paint will reduce your stock!

With the tin of paint in hand, there are two possible ends. Either you finish painting before you run out of paint, in which case you put the tin back on the shelf. Or you run out of paint before you finish painting, in which case you go and buy a replacement tin and loop back to the start of this paragraph.

So there is no painting operation that can reduce the number of tins of paint that you store.

The only kind of operation that can reduce the number of tins of paint you have in stock is one that miraculously requires exactly the amount of paint that you happen to have remaining in an existing tin, or one where you don't care if you don't finish, or you don't care if you use several colours, or you throw away a perfectly good half-used tin of paint.

So that's why you have so many tins of paint.

By using up old tins you may decrease the volume of paint that you have in stock, but the number of tins can only ever increase.