The app that never changed

A music app is popular. For five years the team changes nothing.

A new app arrives. It has shared playlists. It is cheaper. It is faster. Users move to it.

The first app did not break. But it was no longer useful enough. To stay in use, a product must keep changing.

Key words

Word	What it means	Example
Iterative	Done in small steps. Each step improves the one before.	Version 1, then 1.1, then 1.2
Relevant	Still useful to the people who use it.	An app that people still want
Feedback	What users and clients tell you about the product.	The search is too slow
Competitor	Another company that sells the same kind of product.	A different music app that does the same job
Efficiency	Doing the same job with less time, money or work.	A page that loads in 1 second, not 5
Future-proof	Built so it is easy to change when things change.	A fee kept in one setting
Technology	Machines, systems and software that people use.	Faster phones, new browsers
Version	One numbered release of a product.	Version 2.3

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Five reasons a product keeps changing

Reason	What happens	Example
Review after feedback	Users or the client say what is wrong or missing	Many users ask for a dark mode
Developments in technology	New things become possible	Phones now have face unlock
Competition	Competitors add things users like	A competitor adds shared playlists
The need to improve efficiency	The same job should cost less time or money	A slow report is made to run in seconds
The need to future-proof	Make the next change cheap and easy	Keep a price in one setting, not in 40 places

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Try it: one setting, many uses

Code: python

FEE = 3.0

def total(basket):
    return basket + FEE

print(total(10.0))
print(total(25.0))

# Change FEE to 4.5 and run again.
# One change moves every price. That is future-proofing.

The number written in 40 places

data-callouts.warning.label

If a price is typed in 40 places, one change needs 40 edits. You will miss one. Write it in one place and use it from there.