We notify you when your balance drops below $1, which should be enough time to top-up again. In the future we're thinking of having that notify N days before we estimate your balance going to 0.
By the way, the site uses trackingco.de for analytics, so I can give you some free balance to return the favor :)
Good to know about that, because I tried to top up $1 earlier, the browser didn't allow me, then I edited the DOM manually and succeeded in getting a Stripe payment modal -- however it seems that the notification system wasn't ready for misers like me.
Thank you for the free balance, that was very kind!
By the way, the site uses trackingco.de for analytics, so I can give you some free balance to return the favor :)