| http://www.feedersupplier.com/SMT_THROUGH_HOLE
. Whereas, through-hole assembly requires some solder, a soldering iron and a pair of sturdy hands. Although hand soldering a few SM components is possible with a few tools, it can be a fidgety process, especially if you are handling many components that are barely visible to the naked eye
| https://unisoft-cim.com/crosschecking-pcb-component-footprint-and-bom-footprint.html
from the centers of the 2 extreme pins on the device. So for example a 0603 device listed in the BOM would be thought to be 60 mils but the actual measurement calculated maybe slightly more or less. For example in the figure above it is 71 mils for one