Improving Gmail sender reputation is a multifaceted process that demands consistent effort, not a quick fix. While a 3-week lag might be observed before improvements reflect, the actual timeframe ranges from a few weeks to several months, varying based on several elements: the initial reputation damage, the extent and consistency of improvement, and adherence to best practices. Actions like IP warming, which itself can span weeks, cleaning email lists, and providing engaging content are essential. Experts suggest that while consistent positive changes need to be implemented, one must also let older negative data "age out", which can take up to 90 days. Continuous monitoring and flexibility in strategy are crucial for sustained deliverability.