Let me offer the advice that you load enough that will be shot up within ta year.
I have violated this in spades, but I am finding with mid nineties rifle powders, ammunition loaded for years are now having case neck cracks and body splits. Gunpowder deteriorates and as it deteriorates it outgasses nitric acid gas. It is impossible to predict just when gunpowder goes bad, but I am getting to the opinion that it should be shot up no later than 20 years of age. Yes, we all have shot older gunpowder, and yet, I am having issues with mid nineties gunpowder. One particular lot of AA4064, ammunition that I loaded in February, took it to a June mid range match and most of the case necks cracked. Same gunpowder loaded before the match, no problems with the same batch of cases. Conclusion, this stuff is going bad fast but the powder does not have an acidic smell or red dust. It has a neutral smell.
I do have pistol ammunition that I loaded and not shot up since the 80's. Probably not too much of the stuff that old, but I have older pistol ammunition around. The reason I have not had problems with this stuff is just due to luck of the draw in gunpowder lifetime. However, after having enough issues with gunpowder over 20 years of age, and given that cases are not getting any cheaper, I think it is best economic practice to prep the cases, prime where necessary, but only load up with powder and bullet close to the time you want to shoot.
Now there will be those who jump on this and tell me they fired 1918 vintage ammunition, fine for you. But, some of my rifles shoot cases that are getting very hard to find. When was the last time anyone found 257 Robert brass that was not $1.00 to $2.00 a case? I think my 300 H&H brass was $2.00 a case and I was happy to get it. I am going to baby that brass because it may be years till I see the stuff again.