What “legacy” really means
The word legacy is often used as shorthand for something negative. In reality, most legacy Umbraco sites are not broken, outdated or failing. They are legacy because they have not been cared for.
These sites have survived changing requirements, different developers, shifting business priorities and evolving technology. They still deliver value, often reliably, but they carry the weight of every decision made along the way.
A site does not become legacy because of its Umbraco version alone. It becomes legacy when the original intent behind decisions is no longer clear.
How Umbraco sites evolve over time
No Umbraco site starts messy. Most begin well structured (for the time) and ethically built. Problems appear gradually.
Incremental changes and quiet compromises
A new property is added to meet a deadline.
A document type is reused for something it was not designed for.
A template condition is added instead of adjusting content structure.
Each change feels reasonable at the time. None of them are inherently wrong. The issue is that they are rarely revisited.
Over years, these small compromises accumulate into complexity.
Changing hands, changing assumptions
Legacy sites often pass through multiple teams or developers. Each person makes decisions based on what they see, not what was originally intended.
Without clear structure or documentation, assumptions replace understanding. This leads to defensive coding, duplication and workarounds that further obscure the system.
Structure is invisible, but it shapes everything
Content structure is one of the most important aspects of an Umbraco site, yet it is rarely prioritised once a site is live.
Document types as contracts
Document types define how content is expected to behave. When they are unclear or overloaded, editors struggle to know what belongs where.
This leads to inconsistent content, misuse of fields and reliance on guidance outside the CMS itself.
Editor experience reflects structure quality
When structure is poor, editors compensate with manual processes, notes or repeated questions. This is often misdiagnosed as a training issue rather than a structural one.
Good structure guides editors naturally and reduces the need for explanation.
Templates and tight coupling
One of the most common issues in legacy Umbraco sites is tight coupling between templates and content structure.
When templates assume too much
Templates that assume specific document type shapes become fragile. Adding or removing a property can affect multiple areas unexpectedly.
This discourages change and creates fear around even small updates.
Separation of concerns matters
Content should describe content. Templates should describe presentation. Logic should live where it belongs.
When these responsibilities blur, complexity increases and maintainability suffers.
The hidden cost of quick fixes
Quick fixes are often praised for getting things done. In legacy systems, they are usually the root cause of long-term problems.
Copying instead of understanding
Copying templates, partials or code without fully understanding them introduces duplication and inconsistency.
Over time, similar logic exists in multiple places with slight variations, making bugs harder to track and fix.
Technical debt compounds silently
Technical debt does not announce itself. It shows up as slower development, increased risk and growing hesitation to touch certain parts of the system.
By the time it becomes visible, it is often deeply embedded.
Legacy does not mean rebuild
One of the most damaging assumptions is that a legacy site must be replaced.
Rebuilds are not neutral decisions
Full rebuilds are expensive, disruptive and risky. They reset complexity temporarily, but often reintroduce it quickly if the underlying causes are not addressed.
They also discard valuable knowledge embedded in the existing system.
Targeted refactoring is often enough
Many legacy issues can be addressed incrementally:
simplifying document types
consolidating duplicated content models
improving naming and grouping
decoupling templates from assumptions
documenting custom behaviour
These changes improve maintainability without changing the public-facing site.
Understanding before changing
The most important skill when working with legacy Umbraco sites is restraint.
Reading before writing
Taking time to explore content models, templates and code paths reveals patterns and intent that are not immediately obvious.
This understanding allows changes to be made deliberately rather than reactively.
Context prevents mistakes
Changes made with context tend to reduce complexity. Changes made without it usually add more.
Legacy systems punish speed and reward clarity.
Why structure determines long-term success
Sites rarely remain static. Teams change, content grows and requirements evolve.
Structure enables evolution
Well structured sites can adapt without fear. Changes feel predictable and reversible.
Poorly structured sites resist change and grow more fragile with every modification.
Future developers matter
Eventually, someone else will work on the site. Clear structure reduces dependency on individuals and lowers the cost of onboarding.
This is often overlooked, but critically important.
Respecting legacy systems
Legacy Umbraco sites exist because they have delivered value consistently over time. They deserve respect, not dismissal.
Improving structure, reducing friction and documenting intent extends their lifespan and reduces risk.
Understanding why a site is the way it is, and choosing to improve it thoughtfully, is one of the most valuable skills in real-world Umbraco development.
This is an area I continue to focus on and one I will keep documenting as I work with more long-running systems.