The problem is the math is correct on paper. However in the real world people who do the math tend to not translate correctly to the real world - they see the math and they don’t save anything while also keeping the loan. People who hate debt are more likely to pay it off, and then put something into savings so they don’t have to get more debt later.
Lesson: hate debt.
I’m researching building my own because I’m so fed up with only being able to find garbage. Good luck in your journey. I haven’t built my own yet, but all I lack is the time to focus on a project.
Copper slowly dissolves in tap water, so the pipes are only expected to last about 70 years. While we don’t have long term data on PEX, it so far is looking good and plenty of experts expect it to last longer than copper.
Like I said: GET A WATER TEST! if you don’t know what you are working with you can’t treat it.
I personally am replacing the copper pipes (lead solder) in my house with PEX. There is some copper left, but not much. If you can do the work yourself this is likely cheaper than the treatment system. (but I drink RO water anyway because of taste)
What you need is very location specific! What I need in my current house is different from what I needed in my first house. You MUST start with a water test. You can buy a kit at any hardware store. However there is no need - in every city I’ve lived in there is a local company that sells treatment systems that does free water testing as part of their sales pitch. They usually know more about water than I do, and they are familiar with what works in your local area. So give a couple a call and get them to tell you what is in your water and what they recommend, then choose the best bid (not low big, best - that means you trust them to install correctly, and their test results show the system will help). I’m sure there are scams in water treatment, but in general I’ve found them honest people trying to make a living.
Your city water is 100% safe to drink in most cases. Chlorine and microplastics are things used to scare you into buying scams that probably don’t even remove what they claim. Your local water treatment company won’t talk about them.
Water treatment can improve taste. Just because the water is safe to drink doesn’t mean it is pleasant. I drink RO water. (but I’ve almost always lived on a well. One house I had test results to show my water wasn’t safe to drink without treatment, the rest of the places water was safe but not tasty!)
Every house I’ve lived in have benefited from a water softer. The water is safe, but soap works much better without the hardness. My current house is about 7 grains of hardness, which means things work okay without. My first house had 31 grains, the soap didn’t work unless you used a lot and then didn’t rinse off, but it was still safe. I have relatives who live where the water is naturally soft.
I had an iron filter in one house because there was so much iron. However there is no iron in the water in my current house so there is no need for that.
Again, start with a real water test. If you don’t know what is in your water you don’t know how to treat it.
Your take isn’t quite right. Debt is only worth having when the long term payments are less than the long term value. Value is not just money, but don’t lose sight of money. Dept is automatically paid off when you die, which is sometimes a consideration though only rarely. However in between the question is what could you do with the money going to payments instead.
Buying a house - most of your payment would go into rent anyway and you have to live someplace. As a general rule of thumb if you will live in the same place for at least 7 years buying is better, but YMMV. When the house is paid off you live there rent free.
Buying something for your business - check with an accountant, but you should be able to make enough money with it to pay it off and make a nice income.
Buying collectable art. I’m not against it, but it is common for art values to collapse as what is “in” changes. It is also common for tastes to change. Thus not a thing even if you can afford the payments.