My grandfather carefully painted black silhouettes of tools that hung behind his workbench, so he could tell at a glance if anything was missing. (There was a house rule of use anything you want, but it better go back where it came from when you were done.)
He didn't do that with his toolboxes, but all but one of those were locked.
I do find I do this as a sort of a tick, while thinking through my next step while making stuff.
The hangar I just came from has hard rules - if any tool is missing the planes are grounded until the tool is found.
No matter what. So you better don't lose those tools.
"To prevent leaving surgical items inside patients, the Association of periOperative Registered Nurses (AORN) recommends counting all sponges, sharps, and related miscellaneous items at five different times: (1) before the procedure to establish a baseline, (2) before closure of a cavity within a cavity, (3) before wound closure begins, (4) at skin closure, and (5) at the time of permanent staff relief of either the scrub person or the circulating nurse"
Atul Gawande talks about this in "The Checklist Manifesto." I believe he recommmends that the nurses who are keeping track (and people who are following checklists in general) must be empowered to pause the surgery. Otherwise surgical equipment still gets left in patients because of egos.
"No I totally got all the sponges out of the patient! How dare you question my authority!"
Interesting, not to get too far off topic but empowering subordinates to question leaders when they know something wrong is now a huge part of crew management in planes too due to some awful disasters.
I have two ideas for automatic machines in hospitals.
One is hand sanitizer dispensers that counts people entering rooms and beeps until all have used the machine, or even until all people already in the room have used it.
It's notoriously hard to get people to use hand sanitizers.
The other is convenient and fast dispensers that counts tools and sponges as they are used.
Was listening to Atul Gawande on the podcast "Conversations with Tyler". Sponges are now bar-coded (less expensive than RFID, etc.) and scanned during the process to make sure they're not left inside the patient.
He didn't do that with his toolboxes, but all but one of those were locked.
I do find I do this as a sort of a tick, while thinking through my next step while making stuff.