only monetary profit counts? i shouldn't borrow to buy something that makes my household more efficient, like a dishwasher?
If "efficiency" in and of itself is sufficient to justify making a purchase with debt, you will quickly find all of your financial resources going to paying off debt service. Then you find that instead of your tools serving you, that you are instead spending your time serving your tools.
The way out is to only spend cash (or cash equivalent, i.e. to commit to paying your credit card bill in full each month) on items which cannot generate a measurable financial profit for you.
them: "these are not loopholes. these other people say so."
all divine authority is mediated by men.
Plus, this doesn't have anything to do with the original topic.
https://en.wikipedia.org/wiki/The_Oven_of_Akhnai
which underscores the idea that (in rabbinic Judaism—clearly other currents divided over this very issue!) human institutions were given responsibility for interpreting the law, including in ways that create leniencies or apparent loopholes. Although there is probably a better story or example about loopholes in particular.
Baked goods that many people are eating this week for Passover might be a good example, because a fair amount of food chemistry has gone into making some of them fluffy and bread-like, while still not technically being chametz. The mainstream interpretation is that the criteria for being "leavened bread" were authoritatively identified and fixed by rabbinic tradition, and that, if you stay within those criteria, you're fine, even if you produce foods that are subjectively reminiscent of leavened bread.
https://www.allrecipes.com/gallery/passover-bread-recipes/
https://www.allrecipes.com/gallery/passover-cookies/
https://www.allrecipes.com/gallery/passover-cake-recipes/
Fun fact: the oven in question is referred to as תנור (tanur). I wondered if this is cognate with "tandoor", and it is, as both terms were borrowed from Persian.
https://en.wiktionary.org/wiki/%D7%AA%D7%A0%D7%95%D7%A8 https://en.wiktionary.org/wiki/tandoor