I always run the hand calcs first to see if I can depend upon the software calcs. Sometimes the software calcs results force me to revisit my hand calcs and lick wounds there. I find it a good check and balance, and it gives me a good "sense" of the import of what the software calcs are telling me.
But, all in all, I would hate to have to do all those calcs by hand (or slide rule) as I used to do.
rmw