The 8 Wastes of Lean (TIMWOODS) — with Examples

Most of the time in any process is spent on things the customer would never pay for. Lean gives those things names. Once you can name a waste, you can see it — and once you can see it, you can remove it.

The eight wastes (TIMWOODS) — each a lens for examining a single process step.

What “waste” means in Lean

In Lean, waste (the Japanese term is muda) is any activity that consumes time, effort or money without adding value the customer would willingly pay for. It is not about people working harder — most waste is baked into how the process is designed, not how hard anyone tries.

The discipline is simple: separate the steps that genuinely add value from the steps that don't, then attack the second group. The hard part is seeing the waste at all, because it hides in plain sight. That's what the TIMWOODS framework is for.

The TIMWOODS framework

TIMWOODS is a memory aid for the eight classic wastes. The original Lean model had seven; the eighth — unused Skills — was added to recognise that wasted human potential is as costly as any physical inefficiency.

T — Transport: moving work, materials or information further than necessary.
I — Inventory: work piling up — files awaiting review, unprocessed requests, half-finished cases.
M — Motion: unnecessary movement within a step (switching between five systems to complete one task).
W — Waiting: idle time — the request sitting in a queue, the approval stuck in an inbox.
O — Overproduction: doing more, sooner, than the next step needs.
O — Overprocessing: more steps, checks or detail than the outcome requires.
D — Defects: errors that cause rework, corrections or returns.
S — Skills: capable people doing low-value work a system or a simpler step could handle.

How to spot each waste

Waiting and Inventory are usually the biggest and the easiest to find: look for anywhere work queues up. Defects announce themselves through rework loops on a process map. Overprocessing is the subtle one — a sign-off nobody reads, a field nobody uses, a report nobody opens. Motion and Transport show up when a single task bounces between people, systems or locations.

A practical test

For each step, ask: “Would the customer pay for this if they could see it?” If the honest answer is no, you've found a candidate for one of the eight wastes.

Putting waste on the map

The most useful thing you can do with TIMWOODS is tag it directly onto a swimlane process map. When each waste is marked at the exact step where it occurs, the pattern becomes obvious — and so does the priority. A step carrying three wastes at once is where you start.

This is exactly what LeanBean does automatically: describe the process, and it maps it, tags the TIMWOODS wastes step by step, and surfaces where the time is really going.

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Common questions

What does TIMWOODS stand for?

TIMWOODS stands for Transport, Inventory, Motion, Waiting, Overproduction, Overprocessing, Defects, and Skills — the eight wastes of Lean.

What is the eighth waste of Lean?

The eighth waste is unused Skills (sometimes called non-utilised talent): capable people doing low-value work that a system or a simpler process step could handle. It was added to the original seven wastes.

Which Lean waste is usually the biggest?

In most office and service processes, Waiting and Inventory (work queuing up between steps) are the largest and easiest wastes to find — they show up as delays and backlogs.