I've yet to run into a situation where there was only 1 box of ammo I was looking at in caliber. 2 boxes is enough to function test in the gun and burn and load at least 2x.And this is why I tend to shy away from any exotic extremely expensive and hard to find ammo in any semi automatic pistol caliber. Sometimes I'll carry a Glaser Safety Slug or a MagSafe round as the first round to fire in a revolver, and I'm OK with burning up one of those "four dollar cartridges" every couple years and replacing it with a fresh one.
But with semi autos I would want to shoot a whole box of 50 when I first decide to go with that load, and after that I want to shoot whatever is in the carry gun at least once a year and replace it with fresh.
That is extremely expensive and it can be a hassle to replace said exotic / premium rounds.