Thanks for your comments. I guess you are right. If we stop developing for an extended period of time then the personal environment will be recycled.
However, I am also sure (because I have tested it) that if apps are consistently accessed by end-users (or by ourselves) then our personal env will not put on sleep for a long time.
I have many imp POCs and data in my personal env, which I don't want to lose. I don't get time to login and keep developing in my personal env. My personal env was often being put to sleep and once it was recycled as well.
Therefore, I have created a simple application, which I can access regularly to avoid auto-suspension. This component is under development so I will observe the behavior and will publish if it really works.
Since I had more than one personal environment so I had to publish this application in the forge to reuse it in other environments and others can also use and try it.
Please try this approach and let me know if you env still go to sleep.