The OTR GroupBefore you pick a tool, a template or a methodology, you have to decide what shape the work should take. That shape is the project life cycle. This guide draws on the Association for Project Management (APM) to explain what a life cycle is, the three broad types, and a few questions that help you choose.
What is a project, and what is a life cycle?
APM describes a project as a unique, transient endeavour, undertaken to achieve planned objectives. It has a finite timespan, with a definite start and end, and is separate from business-as-usual activity. A project life cycle, in APM's words, is a framework comprising a set of distinct high-level stages required to transform an idea or concept into reality in an orderly and efficient manner.
In everyday language, the life cycle is the route the project takes from idea to finished result, divided into stages so people can see where they are and decide whether to continue.
The three broad types
APM lists three types of life cycle.
Linear (waterfall)
Work moves through stages in order, with each stage largely completed before the next begins. This suits work where the end result can be described in detail up front and changes are costly. Building a structure is the classic picture.
Iterative (agile)
Work is delivered in repeated cycles, with feedback shaping what comes next. This suits work where the end result is not fully known at the start and learning along the way is valuable. Software and product development often use this approach.
Hybrid
A blend of the two. A team might plan the overall stages in a linear way while running some stages iteratively. Many real projects end up here, because few are purely one thing.
APM is clear on one point: there is no universal best approach. The right life cycle depends on the work.
Five questions to help you choose
- How well can you describe the end result today? The clearer it is, the more a linear approach makes sense.
- How expensive is change later on? If late change is costly, more up-front planning is justified.
- How quickly can you get feedback? Fast feedback favours iterative cycles.
- Who needs to see progress, and how often? Stakeholders who want regular, tangible results may favour iteration.
- What do your contracts and governance require? Fixed-scope contracts and stage approvals can push towards linear or hybrid models.
Do not forget the end of the story
APM notes that extended life cycles add adoption and benefits realisation phases to the end of a standard project life cycle. That is a helpful reminder that delivering a result is not the same as achieving the benefit. It also says that sustainability outcomes should be embedded into operations through a structured handover plan. Whichever life cycle you choose, plan the handover as carefully as the build.
APM also lists closing the project in a controlled fashion as a core part of project management, so build time for closure into the plan rather than letting the work fade away.
A quick example
Imagine a team preparing an office move. The date of the move is fixed, the sequence is largely known, and mistakes are expensive, so a linear plan for the move itself makes sense. But choices about how people will use the new space may be better tested in small trials and adjusted. A hybrid approach captures both.
Practical tips
- Write down which life cycle you are using, and why, in your project plan.
- Agree what counts as success early. APM says a project is usually deemed a success if it achieves its objectives against its acceptance criteria, within an agreed timescale and budget.
- Review the choice at each stage. If the work turns out to be less certain than you thought, it is fine to adjust.
Sources: Association for Project Management, What is project management? and What is a life cycle? (read 2 November 2026). General information only.