Review the whole model first
Open the STL and rotate it from several directions. Check that it is the expected part and inspect missing sections or orientation problems.
Check units when size differs
STL does not explicitly define units. If one application interprets values in millimetres and another uses different units, the model size changes. Check both export and import settings.
Use inspection results carefully
Thickness and overhang tools help inspect geometry. Actual printing also depends on the printer, material and slicer settings. Inspection alone does not establish printability.
Keep the original
Preserve the source before converting or resizing. It makes comparing results easier.