手機用一年就要換新的，因為電池不行了；很貴的鞋子，穿了三個月，鞋跟就掉了。

現代生活中，很多產品的使用壽命都在縮短。就像有句話說的，東西壞了，就換個新的，沒人愿意拿去修好了再用。

我們之所以會這樣，除了消費理念的變化以外，其實也是廠家“計劃性淘汰”策略的結果。

Planned obsolescence or built-in obsolescence in industrial design and economics is a policy of planning or designing a product with an artificially limited useful life, so it will become obsolete, that is, unfashionable or no longer functional after a certain period of time.
工業設計和經濟學中所謂的“計劃性淘汰”或“內置報廢”指在設計產品時人為地設定使用壽命，這樣產品在過了一段時間以后就會過時或者不好用。

The rationale behind the strategy is to generate long-term sales volume by reducing the time between repeat purchases.
這種策略背后的理念是通過縮短重復購買周期來促進長期銷售額。

Producers that pursue this strategy believe that the additional sales revenue it creates more than offsets the additional costs of research and development and opportunity costs of existing product line cannibalization.
采用這種策略的廠商認為，通過這種方式產生的額外銷售收入能夠抵消研發成本以及現有產品線同型裝配的機會成本。

In a competitive industry, this is a risky strategy because when consumers catch on to this, they may decide to buy from competitors instead. For example, when Japanese vehicles with longer lifespans entered the American market in the 1960s and 1970s, American carmakers were forced to respond by building more durable products.
不過，在競爭激烈的行業，采用這種策略也有風險。因為消費者明白這其中的策略之后，他們就會去買別家的產品。比如，上世紀六七十年代，使用壽命更長的日本車進入美國市場以后，美國汽車廠商就不得不造出更耐用的汽車來應對競爭。

（中國日報網英語點津 Helen）