Why the actual relevance is often significantly smaller than perceived

Many companies assume that their custom code landscape is extremely complex.

I regularly hear sentences like “Our system is completely customized”.

But the data almost always tells a nuanced story.

1️⃣ A large part of the custom developments is no longer used

Industry benchmarks – for example, in the manufacturing industry – show:

About 56% of all custom developments are no longer used.

In the shown customer example, the value is even 85.3%.

Higher than the benchmark, but with the same pattern:

A lot has been built – little is still needed.

2️⃣ The proportion of heavily used custom codes is surprisingly small

The average value is around 15% in many industries.

In the analyzed customer system, it is only 3.7%.

What does this mean for transformation projects?

Yes – many systems contain a large amount of custom developments.

But: The relevant complexity, meaning the part that still delivers real business value today,

is usually significantly smaller than expected.

This leads to:

• clearer risk assessments

• more realistic project shaping

• fewer technical legacy issues in the core

• and often to a faster, safer project start 🚀

Especially now, as many programs are heading towards 2027 or 2030 milestones, this form of transparency is extremely helpful for clean planning towards 2026.