Mobile hotspot data cycle. Any info please!

I've been with T mobile now for a month now. Can anyone please tell me when do they rest your hotspot data? Is it when they open up? Midnight?  When? I've had nothing but issues with T Mobile since I've been with them really starting to regret it. I travel allot and I use allot of data. I live in GA and if your out my way and have any info on when it resets please let me know. I would really appreciate it. Thank you.