How to observe the wear of non-standard cutting tools

How to assess the wear of non-standard cutting tools? Heat and temperature are important causes of non-standard tool wear. How to assess tool wear.
1) According to the instructions for scrapping non-standard cutting tools, some single product batch production enterprises use it to guide production, but of course, these equipment have high requirements for the accuracy of their use.
2) According to the actual situation, if there are intermittent and irregular sparks during the machining process, it indicates that the non-standard tool has been worn. Look at the color of the iron filings. If the color of the iron filings changes, it may also be caused by tool wear. Looking at the shape of the iron filings, there are serrations on both sides of the iron filings, which are curled and finely broken, irregular.
When looking at the surface of the workpiece, a scratch like luster appears, indicating that the tool may have worn out. Listening to sound, processing vibration intensifies, abnormal noise occurs
The occurrence of burrs on the workpiece, a decrease in roughness, and changes in workpiece size are obvious issues with the tool.