Start with 150 and subtract the number of toilet rolls in your cupboard.
Err!! that comes to 120.
In my defence, as previously stated, I have always had a stock of non perishable items, BEFORE the "hit" the least rolls I had at any one time was 18
Same with teabags, at least 2 packs of 160's unopened.
That's my story and I'm sticking to it......