Engineers love a Weibull plot, but the plot itself is not the point — the shape parameter, β, is. That one number quietly tells you which failure regime you are actually in.

Reading the shape

When β is less than 1, the failure rate is decreasing over time — classic infant mortality. A β near 1 means a constant failure rate. Once β climbs above 1, you are in wear-out, where preventive replacement finally earns its keep.

So before you quote an MTBF or set a maintenance interval, read the shape first.