I use my surveyor every day & change the marker pretty regular, I have noted that a worn marker puts the survey at a new location. I have had PM's telling me the survey can often be done by eye when you get enough experience. I'm still waiting for the experience to kick in, I have tried by eye and then checked with survey, strange how shadows can be so false. An improperly designed cast frame (or digitally printed then cast frame) can easily become an orthodontic or tooth extractor.
If I have that gut feeling that something might move I have sent a provisional brux appliance for use during construction (strangely they seem to continue treating themselves with them). My DDS's have come to respect my judgment and take my hints from time to time, I even get them to pay for the treatment brux, having the teeth not move and having the brux for the patient to use when the partial is being cleaned or the mouth is resting at night is not all that bad either.
If a tooth is at any question don't clasp or combo clasp with wrought wire soldering or welding the round flexible clasp in place. Reducing the I beam from extracting all so soon, just another ideas or two too chew on.