Yeast Starter Concern

Curious, whats the longest time frame you have left a yeast starter on a stir plate? Was going to brew on sunday and didn't prep too well and now I can't do so until friday or saturday this week. My starter has been on the stir plate for exactly 48 hours so I am curious if I should fridge, start another before brew day, let it ride or trash it lol. Another noob mistake from a homebrewer who's learning the ropes... was planning to do my first all grain recipe I've been working on.