My accountant tells me that calculating my costs is critical. I keep telling her that it's a pain and annoying.
However, some simple math for keeping track of costs has made a significant difference in my bottom line.
Here's an example. I get my water soluble stabilizer from a retailer. It costs me $2.15 per yard. From one yard of stabilizer, I can get 8 pieces. I'm paying 26 cents per piece. I pay no shipping, but I've got to drive out the the store and catch a sale. It's an hour out of my working day and I get no embroidery done during that time.
I get my wash/tear away (paper) stabilizer from a commercial source and I pay 58 cents per yard. I get 8 pieces per yard for an end cost of 7.25 cents per piece. I pay shipping, but I shop from home while the machine is running, completing paying work at the same time.
By using the tear/wash away instead of water soluble, I'm saving about 19 cents per item. It doesn't take a rocket scientist to determine that the better thing to do is to use the cheaper stabilizer. For each 5 items, I've got a dollar extra in my pocket.
To further press this point, I live in Florida. Items created with water soluble stabilizer are affected by humidity. The stabilizer shrinks up and causes the items to become wrinkled. They look awful. The only thing that will fix that is to wash the items and iron them after I've embroidered them. Ain't nobody got time for that!
If my goal is to keep my machine running to create items that have high resale value and decreased cost, I'm not going to buy any more water soluble stabilizer. I have a stash that I've got stored in plastic in case I need it for a special job. When I need to use it, I'll charge the customer extra.