SMART Predictive Failure

I have approximately 33 Precision Tower 3420 SFF (upgraded to W10 from W7) that are used in a 911 dispatch center.  More than 3/4 of these machines are showing the SMART Predictive Failure (see below) when running diagnostics.  All of these machines were purchased at the same time and many of them are used 24/7/365.  I have a hard time believing that this error is valid on 25 out of 33 machines.  Has anyone else experienced this on a large number of machines?  We do have spares which do not display this error that we can use in case one does fail, however I would appreciate any input on this issue.