4.  Projected Use-Life

Many life cycle analyses demonstrate that the most materially and energy intensive part of the product's life is the use phase. (If you have not yet done so, look at Product Life Cycle). In fact, the use phase of a product's life is crucial to consider for several key reasons.

Product lives are mostly determined by how long we use them for. But this is often more a measure of how they look than their usefulness. Our cultural habit of throwing things away before their material lives are over ripples back to the production side, encouraging the design of short-life, 'disposable' products. Short-life products are also the result of comparative functional obsolescence, particularly with technologies. So we are encouraged to buy 'the latest' technologies, even if we never take advantage of their suites of new 'whiz bang' functions. Carefully considering how products are used provides a designer with a lot of cultural information, which can lead to the emergence of new product concepts. How we use designed things determines how we value them, how long they will last and what kinds of products we will want to buy in the future. A careful consideration of these factors in the design process can even circumvent the need for environmental management strategies like recycling, by putting design for reuse first.

This stage is particularly concerned with what we can learn about designing for use-life from a materials perspective. In Stages 7 and 9 we incorporate other use-life considerations, like interface semantics and semiotics, though as you will see these aspects need to be considered in relation to materials.

Exercises:

 
1 Following on from what you noted about your proxy in Stage 2, answer the following, as applicable:
2 What does the appearance of the product tell you about its handling, i.e. what parts look most worn out, what parts look unused?
3 Are the worn parts of the product integrated or are they able to be replaced?
4 Do you think this product has been shared or mainly used by a single user?
5 Do you think the product has been well cared for? Why?
6 Is the product hard to clean or care for?
7 Do you think the materials chosen for this product support or detract from its durability in use?
8 What amendments might you make from a materials perspective, to extend the product's life?
9 How long do you think your proxy product was designed to last for? What tells you this?
10 Is the product reusable, upgradable, disassemblable?
11 Does the product indicate to you how to manage its materials at the end of its life?
12 Now referring back to 'Uses' in Stage 1 and 2, map out the intended or 'ideal' first and subsequent use-lives of your product, for example it is a short-term product that can be reused several times for the same purpose (e.g. most baby products) or perhaps a long-life, adjustable product (e.g. some baby products: chairs and beds)? Considering what you have learnt above, write a general description of the material requirements needed to support this and subsequent use-lives of your product, for example, "my product needs to be made from durable, non-toxic materials that do not scratch easily, maintain their appearance and that are easy to clean. The least durable parts (for example, fabrics, foam backings) need to be easily and entirely removable, surface fabrics need to be dark and reinforced in certain areas. All materials need to be joined without adhesives so they can be easily pulled apart at end-of-life. Now consider the following:
13 How will you ensure your product is resource efficient during its use i.e., how will you design it to use less or no energy, water, chemicals for its operation and maintenance?
14 Can you design out the need for exterior sources of energy (e.g. utilise manual pumps or passive body heat?)
15 Will the product be at all hazardous to its users and in what circumstances? Will it give off fine particles or fibres, off-gas VOCs, emit endocrine disrupters? How can you modify any hazards this product may pose to users, or how can these be made obvious to users?
16 How will users learn how to best use, maintain, repair, reuse and prepare your product for end-of-life processing? What if any of these instructions will be embedded into the product materials; will you employ labels, embossing, manuals or ongoing support services?