With factory personal defense ammo, many experts recommend shooting every other round in the box to verify you have not picked up a bad lot of defensive ammo. This seems a little extreme to me, although I will test out 5 rounds from a box of 20 or 10 from a box of 50. Shooting 10 from a box of 20 would get expensive if you were switching out very often, so I only switch out once a year. I may shoot defensive ammo at the range a couple of times a year to make sure nothing in the ammo or the gun has changed.
As to loading a magazine with alternating rounds of FMJ and Hollow points, the only caliber I have ever considered that on was a .380 for two purposes, the first two rounds FMJ for Function and penetration, subsequent rounds of Hollow point for expansion.
However, I have never subscribed to actually doing so. If I was out in the sticks with a revolver, I might load a couple of chambers with snake shot for snakes with the remaining chambers in flat soft points for bigger critters!
If I was driving an M-1 Abrahams or flying an F-16, I can understand the usefulness of different munitions.