Do I need to keep 500k baht in my account each time I enter Thailand on a DTV visa, and how does renewal work after one year?

Apologies if this has been asked and answered however i have just spent the last 30 mins looking. I am looking at the DTV as an option, can someone confirm::

1, Do i need to have the 500k bht in my account each time i enter Thailand ie is there a possibility it will be checked?

2, after 1 year do i need an extension or is it valid for 5 years? The info here is confusing, my issue is if i am not in Thailand on the anniversary i would need to make another trip to renew every year?

Thanks,