I think a check weight for the load you are using is a valuable way to monitor your scale.
For things like the 300WM a 5 gram weight, down to a 2 gram weight for .223 loads.
Your scale might require a full scale calibration weight but checking it's accuracy @ the target value adds confidence.
A really small sensitivity weight (10 milligram would be adequate) will prove the capability to sense small changes in measured value.
As far as the Quality of the weights look up weight classes and tolerances. The cheaper weights are usually Chrome/Nickel plated magnetic steel.
Usually just fine. Better weights will be made of nonmagnetic stainless. For those of you that spent the money to buy a high end milligram reading scale, why not a check weight good to a milligram? Price out tolerances
You really want 'Sameness'. Having a full scale calibration weight is fine but a check weight and sensitivity weight can prove long term
Sameness.
Now to the poster above me that went with the Amazon cheap check weight, that's just fine.
Get a container to protect the weight just like you spent a few hundred dollars for it.
Take care of it and it will be almost exactly the same 100 years from now?
Not saying it's 'on the money', just the same as the last time you used it.
One quality control technique for monitoring weights is to get a continuous set.
1,2,3,5 sequence or 1,2,2,5 sequence not a 1, 2, 5 sequence.
1g, 2g, 3g, 5g 10g. or 1g, 2g, 2g, 5g, 10g. Not a 1g, 2g, 5g, 10g.
By having more than one combination you can check for group and individual changes.
Have doubts about your 3 gram in a 1,2,3,5 set because you dropped it?
compare it to your 1g and 2g.