If you want to get prestige the fastest possible - just do everything you can til like 2 prestige then reset. Takes 5 minutes and you'll have tons.
If you cba with that like (hopefully) most of us then i would say a good time to reset is when getting anywhere will take too long.
In my case i reset once per day. At that point i boost up Cassie until i unlock bowhunting and then Elle until i get the last 4 hobbies. Once i have those i play a bit more to do anything i can do immediately, put in as many jobs as i can on top of having all hobbies on, then head to bed. Once i wake up i fix better jobs that have unlocked and head to work.
After work i do everything i can until i will have to wait for a long time (1-2 hours) and then reset it. Nets me a fair amount of prestige each day, typically 80ish but was less when i had lower speed.
Edit:
Here's my current stats for the records.