One thing any beginner or advanced grip trainee can spend a lot of time thinking about is workouts per week. Hopefully, I can enlighten you in this area. Here are my thoughts that have developed over the past few years...
The Big Workouts
If you're planning on doing a big workout with lots of negatives involved you'll find that you may need at least 3 days rest in between workouts.
Currently, my Friday workout is my "biggest" workout of the week. I'm working my way toward 60 negatives with each hand. Saturday morning my hands are shot and they have been staying swollen all day. Not swollen in a bad way, per se, but the kind of swelling that occurs during summer on a hot day. I put 3 days before my next workout, which is Tuesday evening. For me, that seems to be just the right amount of time.
Lots of Reps
If you're just getting started or find that doing reps work good for you then you can most likely get away with an every-other-day schedule or a 3 days per week schedule, which seems to be popular among some trainees. I did this when I first got into gripping and it seemed to work very well. My hands toughened up and gains in strength came quick.
Listen To You Body
It is very hard to tell someone what to do exactly because each of our bodies react slightly different to these types of things. I believe the best recommendation I can give you is to say just listen to your body and don't be afraid to find out what works best for you. It's up to you to find out what works best! Good Luck!