帮我用学术的风格去修改这篇文章的错误：Product life cycle is a theory of predicting different sales stages of products. Product life cycle has four stages: introduction , rapid growth , maturity and decline.  The product life cycle can help companies better predict the various stages of a product and adopt different marketing strategies. The product life cycle can be defended as a technical methods ,which can assessed the companies to achieve their coals. This essay will talk about whether the product life cycle is effective in practical applications. Then this essay will analyze the strength and weakness  of the product life cycle, and provide iPod and tablets as the examples to analyze whether the product life cycle is effective Furthermore, this essay will claims that the product life cycle can help companies better predict the various stages of a product and adopt different marketing strategies. This essay will outline in four stages in PLC, include the  strength and weakness of PLC . In addition, it will discuss a  tow cases study from previous research.
The concept of Product life cycle has four stages. The first stage is indoctrination,  during the introduction stage, the product is continuously promoted through advertising to make more people aware of the product, while also cultivating user stickiness. In the early stages, manufacturers modify, update, and improve their products so that new products can receive attention and ensure that they do not enter the decline stage too early.(Mariachiara Restuccia, et al., 2015) . The second stage is growth, in this stage, the product enters a period of rapid growth, and sales have made significant progress compared to the first stage. The third stage is the maturity stage, during which sales no longer grow at a high speed like the second stage. The fourth stage is decline, as new products enter the market, it may be gradually replacing old products or reducing demand for old products, or it may be due to market demand saturation. The sales of old products continue to decrease until losses occur. Only companies with strong brand appeal can still make profits, while most manufacturers will lose money and most of them will exit the market (Waschik, R, et al., 2010). 
The first strength of is company decision-making. It serves as a reference for marketing strategies, allowing companies to determine at what stage a certain product market is in, whether it is worth entering, and whether it can be profitable at this stage. Golder and Tellis (1993)  “ ...... report that brands that enter after the pioneer, during the growth phase of the product life cycle, outsell pioneers in many markets.” Another strength of PLC is its strategy which is very important for a company and it will directly affect its profitability. Venkatesh S et al., (1999)  argues that he has developed a dynamic brand sales model using data from 29 brands in six pharmaceutical markets, studying the different performance of different stages of the product life cycle on sales and market. Research has shown that in the growth stage of the pharmaceutical market, sales can rapidly expand, occupying a higher advantage than the companies that developed this drug in the introduction stage (Venkatesh S et al., 1999).  In the growth stage, latecomers do not have to bear the marketing costs of the growth stage and do not need to cultivate user stickiness. At the same time, there are relatively few competitors in the pharmaceutical market, with high profit margins. Compared to entering the market in the mature stage, entering the growth stage results in better profits, less competition, and lower marketing costs.
 There is evidence that PLC has many benefit for companies. For example, the product life cycle can make sales forecasting easier. With this model, companies will have more confidence in making marketing decisions. The author uses Samsung as an example and believes that with sufficient experience, it is easy to predict how long sales will peak through the product life cycle and predict when sales will decline (Hitesh B, 2023 ). It will be important to predict the sales volume to determine what stage this product is in and when it should be taken out of the market. Under normal circumstances, the entire life cycle of Samsung's products will last for two to three years, but there are also exceptions. 
Apple iPod is a typical example that includes the entire life cycle of a product, which may prove the effectiveness of the product life cycle in practice.  At the time of its release in 2001, it was in the introduction stage and the newly launched iPod was priced at $399. Although this product has a unique aesthetic design, not many consumers pay for its expensive price. However, Apple persisted and, following a rigorous three-year period of iterative enhancement and fine-tuning, unveiled a novel iteration of the iPod. During this period, the price of the iPod decreased, and the product became more distinctive. At this time, consumers began to recognize this product and were willing to try it, marking the second stage of iPod growth. The best-selling of iPods is not a coincidence, as their versatility has been loved by various institutions and universities, making them gradually becoming a popular product. (Deborah L. V  , 2006).Due to the popularity of iPods, there are constantly competitors entering the market, and the competition has become fierce. The new competitors are gradually eroding the profits of the iPod, but the brand influence of the iPod is still there. Although the profit margin is not as high as the growth stage due to fierce competition, it still maintains profitability. In 2014, MP3 began to enter its fourth stage of decline due to the impact of smartphones. In 2014, Apple discontinued the iPod classic, but did not stop producing other iPods. It is obvious that Apple recognizes that the iPod has entered a stage of decline. However, Apple doesn't want to withdraw from the market immediately, just gradually discontinuing production of related products. By 2022, the iPod had finally reached the end of its life, and Apple had decided to discontinue all series of products.
In the other hand, PLC  has many drawback some them is in short-comings and other long-comings. One drawback of the product life cycle is that it is difficult to distinguish which stage the current product is in, as there is no clear defined standard. When a company does not have sufficient sales details, it may lead to the company making decisions that are not conducive to the product. “It may make some hastily decision for example cutting on its advertising budget thereby facilitating further decline inits sales” (Haes, et al.,  2008). When a company needs to increase its marketing advertising budget but determines that the product is in a declining stage, the product will be sentenced to death, and the company will also lose a lot of profits.
Another drawback of the product life cycle is the constantly changing market conditions. When selling a new product, the market environment cannot remain unchanged, but constantly changes. The new products launched by the company may not necessarily go through the entire life cycle, and special situations may arise in some extreme situations.  Tibben L (2002) stated that in some food industries, products may not necessarily follow the product life cycle. There is a possibility of a rapid increase in sales followed by a sharp drop, and then the product begins to mature. However, other products can repeatedly switch between growth, maturity, and decline stages. The ever-changing market environment is unpredictable, which is not a favorable situation for the company. When a company encounters a changing market environment, what decisions need to be made becomes crucial.
Moreover, the product life cycle also has its disadvantages, with tablets being a typical example. Since the introduction of the iPad in 2010, the entire market has achieved impressive results, reaching 17.6 million units. In 2011, tablet sales grew rapidly, reaching 60 million units, an increase of 240.9% compared to the first year. The growth remained rapid in 2012, reaching 163 million units, and 195.3 million units in 2013. Tablets seemed to bypass the first stage of the lifecycle and entered the second stage. However, the rapid growth was not sustained, as tablet sales in 2014 only reached 230 million units. From 2015 to 2017, tablet sales experienced negative growth. In 2015, there were 268 million units sold, while in 2016, it decreased to 174.8 million units. It was not until 2019 that a rebound occurred, but the growth was slow. Electronic products such as the iPad have undergone rapid growth and significant design changes, resulting in a significantly shortened lifecycle (EPA.gov. 2016). Using the product life cycle to estimate tablet sales would result in inaccuracies because the growth and decline of tablet sales occur rapidly. Additionally, the ever-changing market environment constantly influences sales, such as the rise of smartphones with touch screens and the COVID-19 pandemic forcing students to attend online classes, which spurred a rebound in tablet sales.These weakness indicate that the product lifecycle is not necessarily accurate.
This essay has evaluated the product life cycle in terms of marketing strategy.  Moreover, this essay has discussed the tow cases study for iPod and tablet . It seems likely that the product life cycle can help companies to develop better strategies, understand what stage their products are in. The enterprises should take steps to ensure that use PLC property. Firstly, Choosing the right product or market is crucial. The market is often better predicted than a single product, and a product may be difficult to predict trends, but a market is relatively better predicted.   Secondly, companies need to flexibly use the product life cycle. The product life cycle cannot be rigidly applied because it may not 100% correct. When using this theory, it is necessary to apply it flexibly, analyze it realistically, and make decisions based on reality. Overall, although the product life cycle is not perfect, it still has certain reference value. In practice, companies can refer to the product life cycle to make some decisions. The product life cycle allows companies to know when their products will enter a decline phase and introduce new products to maintain market share.