Yield on Cost

One more consideration for a solo product: which of these can you undo. Raising new prices is reversible next week if signups collapse. Selling 140 people a separate SKU is a decision you are still administering in three years. Prefer the reversible option when you are guessing.

I weighed it for a month because I got tired of guessing too. Four hybrids went through just under 500g of pellets a day between them, so roughly 120-125g each, and a 20kg sack lasted me a bit over six weeks. Winter pushed that up about 15 percent because they burn energy keeping warm and there is nothing to scavenge. Add a bag of mixed grit and a tub of oyster shell that last months, and my all in feed cost per dozen eggs came out somewhere near what supermarket free range costs. You do not save money on eggs, you buy better eggs and a hobby.

Bin the pull-through first. It grinds a fresh, badly angled bevel every time you use it, which is why your knife is blunt again within a week - you're removing steel, not maintaining an edge. A basic combination stone and one afternoon of practice will make your existing supermarket knife outperform a £60 knife that you keep dragging through a carbide V. Do that before you spend anything.

Use it for pencil, ballpoint or drafting and buy something else for the pens. A 200 page notebook is not worth fighting for a year.

Politely disagreeing with the whole framing. You are testing at the stone and asking it to predict a week away, and it cannot, because retention is mostly about the steel, the angle and what you cut on rather than about how the edge left the stone. Two knives that test identically will diverge completely if one lives on a wooden board and the other on glass or in a drawer full of other metal. Before you buy any test, check what your board is made of and whether the knives touch each other in storage. That changed my retention more than any sharpening change ever has.

Two plus budget for paper and ink is a better plan than either of the ones I'd given myself.