Glue boards are not necessary inside "tin cats" ... they are designed specifically to only allow rodents to go in, not out. Once a mouse goes in, it is in the trap for good. That being said, there are two types of tin cats - one with a solid metal lid, the other with a clear plastic window. I prefer to use glue boards in the ones with the solid lids to ensure nothing jumps out at me when I'm checking the traps on a regular basis... but they aren't necessary. A secondary benefit of glue boards is that you may be able to identify certain types of insects that may be running around your facility. You need to weigh the benefit vs. the cost of placing glue boards in all of the traps and replacing them as they get dirty.
We use a combination of in-house checks and an outside Pest Control Operator. Our PCO comes in every other week, checks all the traps, the bait stations outside, all of that. Then, a trained designated employee will go around and quickly check the traps daily to see if there's any activity, and that they are all in the correct position based upon our maps.
Make sure you have documented training for anyone who is performing this task. If you do have outside bait stations and are using any pesticides, this will require a great deal more training, MSDS sheets, info sheets, a register of acceptable pesticides, and training of your employees as to
A) What to do if they see bait that has fallen out of the traps for some reason
B) The fact that bait is a controlled chemical and only trained, qualified individuals should handle it
C) what to do in the event they accidentally handle it
D) the fact that it is not allowed in any processing areas.