Determining Gmail spam folder placement rate is challenging due to the lack of a direct metric in Google Postmaster Tools (GPT). While GPT provides some insights, the spam rate it shows is based on user-reported spam, not actual inbox placement. As such, a combination of approaches is necessary. Domain and IP reputation are sometimes considered meaningless, and the focus should instead be on spam rates. Seed lists are valuable for testing inbox placement by tracking where test emails land across various email providers. Several deliverability testing tools, like GlockApps and MailMonitor, can automate this process and provide detailed reports. In addition to testing, improving sender reputation, authenticating emails (SPF, DKIM, DMARC), maintaining consistent sending volumes, segmenting email lists, and promoting high engagement rates (opens, clicks) are crucial for avoiding the spam folder. Understanding how different ISPs filter spam and utilizing feedback loops (FBLs) to analyze user-reported complaints can also inform deliverability strategies. Finally, maintaining consistent IP address activity, delivering relevant content, regularly cleaning email lists, and avoiding blacklists are essential for optimizing email delivery.