Housing benefits and the financial impact of buying a house is regional. None of us know the future, how can you determine 10 or 15 years down the road?

That would assume you would know what the markets would be doing in 15 years or on whether or not the person knows in advance how long they intend to be in the house, or what the RE market will be when they go to sell

I'm a 68 yr old software developer - MS Comp Sci, Penn State, 1971.

I'm working on a startup that calculates the long-term impact that buying a house (or any large financial decision)

You need a spec (a specification). What are you trying to do compare different investment classes?

Everyone who buys a home will hope it appreciates over time. But there is maintenance, big items like roofs / driveways / plumbing nightmares - the list goes on and on. Also a home may become more or less desirable, say because a large industry leaves town.

Now if you buy a Porsche, say for $125,000 it is guaranteed to depreciate.

In order to make a large financial decision the average person will have to borrow money. The bank that loans you the money, must agree that what you are buying is a good enough asset, that they can sell if you default on the loan.

It's common knowledge about what you can afford as a mortgage payment, in relation to your income.

That's already been developed in various programming languages.

I saw it first in FORTRAN in the late 1970s.

https://programmingbydoing.com/a/magic-8ball.html

To the OP-if you're really a student of economics and you're asking strangers for advice, for an app you hope to put out into the world. you might need to go back to school. From a 53 year old who's survived several hard Recessions, I say you and your app are definitely not needed.

There wears something like this in NYT web article. It has default values filled in, but allows the user to adjust the parameters for things like: how long will you stay in the home, what are you currently paying in rent, at what percent annually will your house value appreciate, at what rate will your rent increase, how much property taxes are in your area, how much you'll pay in maintenance. It's not a guarantee, but it's kind of interesting to see how it would play out

"Now if you buy a Porsche, say for $125,000 it is guaranteed to depreciate."

In the mid 1950's a Porsche 356 roadster sold for about $4000 ($36,000 in 2017 dollars). At auction today they routinely bring $150,000. Perhaps you need a different example.

Julian,

It really can't be done and more importantly it shouldn't be done.

It is easy to calculate the financial impact of 100 people buying 100 homes. We can control for cost of living in an area, we can control for rents in an area, and we can even control for economic forecast of an area. We can also look at likely maintenance and control for that. In fact, it has been done many times before.

However, none of this translates into whether or not one person should buy one house. What is impossible to control for is whether or not a single house will appreciate. Areas change very rapidly, 10 years can see an area dramatically increase or decrease.

Also house maintenance is easy to determine on average but impossible to determine for a single home. I have a friend whose house is about 20 years old and he paid about $200,000 for it 6-8 years ago. He found an extensive problem that had been there from the beginning, but was hidden, and had to spend $40,000 fixing the problem. His neighbor's house is the same age, about the same size, in the same style, from the same builder and it doesn't have the problem. Even though their two houses have the same value and would sell for about the same money, he has spent $40,000 more than his neighbor.

So any app that tells an individual that they should buy a home is going to run into some serious issues.

Julian,

If you want to build an app, one that I think most folks would find useful is to provide comparison framework(s) for common financial decisions, such as the break-even point for a particular choice, payoff interval, etc. The framework app should ask all the right questions to get the necessary data, and then provide a financial comparison of 2-3 options.

For example, when someone is renting, but considering a home purchase, most want to know how the costs compare and how/if/when they might "get ahead" by choosing either alternative. All markets differ for the monthly cost of rent/buy, interest rates are a major factor, initial cash cost is different, expected length of time in the home is important, etc. It would be useful to have a framework where they could either work forward from the known values (current rent, down payment money in the bank, etc.), or even work backward from one value to find another (at what price would a home purchase be financially feasible, based on my current rent cost?).

There are many interest rate calculators and other individual apps that calculate pieces of the financial comparison(s), but very few that provide a larger framework for making financial decisions. Most people don't know how to put all the factors together and make an informed decision, so they just make a "seat of the pants" financial decision.

Bruce