This is not a resignation letter - I intend to hang on for dear life.
BBC: Should job-hogging over-50s all resign?
Most startups are happy to find any customer, and will hang on for dear life to every one.
FORBES: 5 Ways to Keep the Right Customers for Your Startup
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。