I keep enough ammo to feed most all of my range toys in my range bag. If I am leaving work, and going to the range I would have to go home anyway. Now if I am out, and about in the country with my truck rifle I keep at least a box of ammo for the hand gun, and the truck rifle to plink with. Most times I will also have a .22lr with a brick of ammo for that as well.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.