I just wrapped a film where the lead actor had to have an earwig at ALL TIMES. Not just shooting and rehearsals - they could not be on set without a fully functioning earwig that was tested and confirmed working. It was their security blanket just as much as it was needed to deliver lines. It was a very sensitive situation and everyone from the director, the actor, and their people were nervous about it. I thought this post might be helpful on the technical side of things to illustrate our workflow.
We were more or less forced to use the Roger 2.4GHz system which ended up being fine with only 2-3 little range issues throughout the entire shoot. I had built a rig that was essentially a Roger Base Station and a BST 216-75 with a mini-mite antenna so I could seamlessly switch between the digital system and the analog system if there were issues. These were both powered off an Omni Charge 20+ battery and either could be fed by a 411 for unlimited mobility and portability. Of course the system could be broken down as needed if it had to go under a couch, etc. The problem with the digital system is that the range is sub-par for what we do, but the 411 makes up for that.
All of this sadly ended up becoming the backup system since talent and their people demanded they use the exact pieces of gear they had been rehearsing with in prep, which was the Roger Touchscreen Mic (a mic and transmitter in one), which alone, could not cut the muster because again, the range is not the best and the reader had to be far enough away so as not to disturb the scene/ruin the sound. So we used x4 Roger Repeaters, usually 3 between the reader's station and the talent (with one or two being hidden on/near set), and then usually the 4th one in the boom op's pocket.
Day 1 was an overnight with a medium length walk and talk and the reader was forced to walk with the scene to keep within range, which was my original suggestion despite an absurd amount of pushback.
The other half of the equation was monitoring. It had to be a 2-way communication system. The reader always had to be able to hear talent. I knew this would need to work during company moves while they rehearse the next scene, or first thing up while we're unloading the truck. So after some trial and error, I tuned an LR directly to talent's SMQV and fed it into a headphone amp, so no matter what I'm doing or where my cart is, the reader could always hear talent as long as they were wired. It bypassed my system completely. The only downside is that the actor has no privacy from the reader, but their relationship was such that this was not an issue.
Sometimes talent was being wired while we needed to test the range on the earwig, so their transmitter was not available. For this, we used a separate talent transmitter in IFB mode and an R1a. This was because I don't like having two transmitters tuned to the same frequency, even if only one is used at a time, just in case the reader is off somewhere with the rehearsal-mic and we can't turn it off for them when talent lands. A stand-in would wear the earwig and the rehearsal mic while the reader wore the touchscreen mic and the R1a. They would assume their positions and the stand-in would walk through the marks and report back if it went out of range.
In the end, everyone was thrilled with how well it worked. There were only a couple hiccups, which, for what we were doing, was to be expected.