Depends on what you are looking through. In my experience, the more halves I looked through the more skunks I got, but this is pretty obvious as most of my half boxes are skunks. Started with 2 a week and grew to 20 a week. Skunk, skunk, skunk.... In my area,There are many people looking through halves based on the number of tellers I talk with, so I gave them up and went to dimes only. I do not see diminishing returns on dimes at all. When I would do a few boxes time to time, I was averaging 1-2 per box, with the occasional skunk. For the past 2 months, I average 30 boxes a week and my returns have stayed the same. Dumping is a MUCH easier process also. Counters in my area did not like the halves at all - I can dump 2K in dimes nearly twice as fast as the halves.
I wish I lived in an area where halves were still producing, but when you go 50+ boxes in a row without a single silver, it appears the well is dry so it was time to mine for something else.
Good luck to you.