Batch method (I call it my coffee can method):

Do everything one step at a time, completing everything before going on to the next step in the process.

I frequently resize 1500 to 2500 pistol cases at a time. Then I decap and neck-expand all of them. Then I will prime them all. When I want ammo all I need to do is decide how many I want, charge with powder, seat bullets and I am done.

The time savings comes in not having to constantly be setting up and adjusting dies, powder measure, etc, for each box or two of ammo.

Saturday evening I resized 2000 rounds of .38 Special. Sunday evening I decapped and neck-expanded. This evening I primed. Couple of hours each evening, now I can load 5-600 each evening and by the end of the week I'll have .38 Special range ammo for the next year or so.