If you can, draw a fine line exactly on top of/over what you are tracing.
Then cut in/on the middle of the line.
If it's an applique type thing, it probably wouldn't make a huge difference.
If it's for pieces that will be pieced, it does matter.
Example: If you are making a nine patch for a 6 inch finished block - if the "extra" is only 1/64 inch per edge - that's 12 edges - 12/64 = 3/16 = which is almost 1/4 of an inch.
Do make a test block to check your "personal measurements" -