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Comment by raldi | Hacker News Reader

Throwing out all your code and rewriting it from scratch is like demolishing your building and constructing a replacement from scratch. It's usually not the right thing to do, it occasionally and rarely is the right thing to do, and it's always the tempting thing to do.

It's stupid to argue, "You should never tear down a building" (like http://www.joelonsoftware.com/articles/fog0000000069.html implies) and it's also kinda stupid to write an article entitled, "Why We Tore Down Our Building (And Why You Should Too)"

Neither is universally right. The right thing to do in a given situation is a difficult and complicated question to answer, and it depends on the building in question: how big it is, how well it was designed, how well it's been maintained, etc.

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Right.

In this case it was 3 months worth of code. I think the analogy is closer to "we tore down this clay hut we built". Easy to build, easy to tear down.

If this were a mature code base, I would be a little more shocked.

Or maybe closer to "We're putting this model building in the closet since we built the real one."

>"like demolishing your building and constructing a replacement from scratch. It's usually not the right thing to do" Actually, tearing down a building and rebuilding is very often the right thing to do, but isn't done for the same reasons people don't toss their code and rewrite from scratch - sunk costs.

Unlike software, new buildings are almost invariably significantly more efficient and less resource intensive than old ones - and green building has, of course, gone from a fringe movement in the wake of the Rio Summit, to the mainstream and is now standard for public and corporate buildings.

Like poorly written software old buildings are expensive to operate and maintain (and unlike well written software buildings still deteriorate over time when left only to their own devices). Finally, like software one must go through old buildings and figure how systems were designed and installed and patched in order to modify them - and this is very time consuming. Per square foot costs of renovation are commonly as much or more than new construction.

How often do you build a prototype building? Or a building as a side project?

Your analogy fails, sir.

It's easier and more common to write dirty code that functions as it should than build a building with poor foundation but that looks and functions as it should.

People build temporary structures all the time -- event tents, for example. And plenty of people finish a room, redo a bathroom, build a treehouse or a shed, etc, as a side project. And believe me, it takes a high level of expertise to inspect a building. Many of the most important kinds of flaw are only evident to the eye of an expert.

Yup, but a tent is not a building. And going from a tent to a building requires you to take apart the tent in almost all cases, no?

I think it's a good one. Think of commercial real estate. You have an old shopping center that is cash flowing. Its maintenance costs are high, and the rent is low. Once upon a time it made sense for the market and the style was perfect. Now it's out of date and the units are not exactly what people are looking for.

You could tear it down and build a fancy new one that would cash flow even more with higher rents and lower costs. It's exactly what the market needs today. Green energy, nice, open spaces, new paint. Do you break out the bulldozers?

It depends, of course.

> How often do you build a prototype building? Or a building as a side project?

This is one of the most amazing things about rapidly growing cities in most of the world. Neighborhoods that start out as informal shanty-towns full of lean-tos with leaky roofs become, over the course of years, first neighborhoods with modest but permanent cement block buildings and tin roofs, and sprout all the typical urban amenities like power lines and sewers (often at first pirated ad-hoc from other nearby neighborhoods), have their roads paved, etc., and a few decades later look like normal neighborhoods, sometimes even surprisingly gentrified ones.

Absolutely, as someone who grew up in a city like Mumbai, I know much about shanty towns and from my knowledge of them, they are far from ideal. ie. They are not know for a strong foundation, cleanliness, longevity etc. They are constantly hacked and patched by its residents to ensure basics like protection from rain, electricity and basics like a toilet.

And that's how New York and Rome and Shanghai grew into world cities. They didn't pave them over and start from scratch. They grew out of shantytowns.

But wait, we were talking about buildings, not cities. A city is made up of many buildings. And buildings are torn down across cities on a daily basis.

Right, and chunks of code are thrown away on a daily basis.

The question is: which is the more appropriate metaphor for a project? A building or a city?

I agree with the position that it depends, code may be a building, or a city or any number of things.

I disagree with the OP that deciding to recode can simply be compared to tearing down and making a new building for no reason. That's oversimplification.

First, there are times when buildings must be demolished and built from scratch. The OP makes this idea seem ridiculous but it happens everyday when buildings are in fact demolished and rightly so. Second, fewer buildings are demolished and built from scratch relative to programming projects demolished and built from scratch due to the inherent differences between a coding project and a building project. For one, the former is more regulated and carries more physical risk than the latter(a coding project).

People might think coders are a bit self-important if we start analogising our project's as cities rather than buildings.

Maybe some projects are more building innovation centres, that later go on to be used within actual buildings, and some don't get used.

My local zoo actually built a full-size prototype of their new penguin exhibit ahead of building the exhibit itself. Once people could actually walk around in the space, some improvements were obvious.

Here's an example:

http://www.vt.edu/about/buildings/surge_space_building.html

"The building provides space to temporarily house academic or administrative units that are displaced because of renovations to their home buildings. The facility was designed using a pre-engineered steel frame with its exterior clad in metal panels and precast concrete-like panel accents. The building is designed to be disassembled and recycled in 10 or 15 years.

One floor; 45,000 square feet. Find a public access defibrillator in the hall intersect."

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