Actually, looks like you could leave pinging on and Heroku will just force "exhausted" free dynos to sleep after 18 hours:
"During the beta period you’ll only get an informational email. In the future, we will force exhausted apps to sleep until they have been idle for at least six hours of the past twenty-four hours." -https://devcenter.heroku.com/articles/dyno-types#dyno-sleepi...
"During the beta period you’ll only get an informational email. In the future, we will force exhausted apps to sleep until they have been idle for at least six hours of the past twenty-four hours." -https://devcenter.heroku.com/articles/dyno-types#dyno-sleepi...