The recommended amount of connects to boost proposals on Upwork to increase the chances of winning projects is not a fixed number as it depends on various factors such as the competition for the job, the budget of the project, and the freelancer's experience and skills. However, it is generally advised not to boost every proposal as it can become expensive and may not necessarily lead to a higher chance of winning the project. It is recommended to carefully select the proposals to boost based on factors such as the client's history, the budget of the project, and the freelancer's relevant experience. Additionally, it is important to keep in mind that boosting a proposal may not guarantee success and it is equally important to write a well-crafted proposal that showcases the freelancer's skills and expertise.