This whitepaper offers a thorough framework for comprehending and utilising the Digital Research Infrastructure Lifecycle Model (RILM), considering the requirements for consistent procedures, coherent governance, and adherence to changing European laws. The paper outlines the important phases of the lifecycle of digital research infrastructures, including concept development and design, development, operation, and eventual termination. There are unique opportunities and problems at each step, especially when considering new technologies and sustainability requirements. The whitepaper identifies and clarifies the wide range of stakeholders, including policymakers and administration of RI, users/researchers, technical operators, and reseearchers on infrastrcuture, building on the strategic insights from the European Strategy Forum on Research Infrastructures (ESFRI). By defining and clarifying these actors' roles and duties, it offers a useful framework for cooperation and decision-making throughout the lifecycle. Analysing lifecycle assessment methodologies, including examining best practices, instruments, and indicators currently used to measure RI sustainability, performance, and impact, is a crucial part of the whitepaper. Stricter rules and guidelines like the Corporate Sustainability Reporting Directive (CSRD) and the European Sustainability Reporting Standards (ESRS), which affect how infrastructures must plan, measure, and report their operations and societal contributions, are increasingly influencing these assessments. For policymakers/infrastructure administration and technical operators, the whitepaper provides proposals to enable successful lifecycle governance. Guidelines for strengthening interoperability, ensuring regulatory alignment, promoting long-term sustainability, and boosting strategic planning are among them. In order to match technological development with policy objectives and stakeholder needs, a unified lifecycle strategy is essential, as the study concludes. The annexe of the whitepaper, which supports transparency and future-readiness, contains a public guide to the ESFRI Roadmap 2026 and reporting requirements under ESRS and CSRD. These tools are crucial for organisations working on ongoing and planned research infrastructure initiatives.