Hi Rx, thanks for reading through that long, vague question. What I actually wanted was a check on whether the user has updated the unbound controls and is now ready to save the next piece of the invoice to the table. I looked at ways of doing this using Wait, but it was all too complicated. I think I found a simple way to do it with a modeless messagebox that waits to iterate through the loop until the user updates the form and clicks ok on the messagebox. I am still ironing it out, but I think this is the best solution to my problem.
Your last question:
I think the crux of your question is - If running some process - how to determine if somone has visited (and maybe more importantly visited and changed data) since the last process was run.
If that is the case: (if not, maybe a little more details)
A table design can include a timestamp field. I typically include two. One for the createion data/time and one for the Last updated date/time.
The default for the created is NOW() (or now)
The table for the last updated - set the value in a hidden field to Now
If the question can be a little more focused - I bet you will get a lot of great advice.