I usually process my brass in batches. Since I usually only shoot the cases through an individual rifle or handgun, I don't bother with sorting, if it is .243, 25-06, or .270 they all go into the same bucket or bag for that caliber. When I get low, I tumble, then check the length, size and trim if necessary and tumble again simply to get the lube and any little burrs off the necks. This is by and far the most work I have when I am getting ready and the trimming in some cases is the most hated part of it all. This is simply due to the fact I have to ream and clean all of the necks on the calibers I don't have the three way trimmer pilot for. UUUUUGGGHHHH I hate hand reaming the necks.....especially on pistol and revolver cases that have had to be trimmed.
When it comes time to load, everything is usually prepped and ready to go. I use the Lee hand primer and will sit in front of the tube and prime up what ever I need to fill the empty plastic cases. If it's a hundred or several boxes of 50, I will have everything primed up and ready in a zip lock bag waiting for the next evening or until I get to them. When I start loading I go through one bag at a time, no matter the count. I usually work up my loads with thrown charge weights, and as such when I start loading I set up my measure to the last noted setting, check the weight several times on the scale, and get to it. I throw them one at a time and when done I inspect the level and seat the bullets. I load 98% of my ammo on a single stage even though I have a progressive sitting three feet away. It simply isn't as easy to set up for each different caliber the way I load. If I am interrupted for any reason, I simply finish the one bullet I have in my hand at the time and the rest can sit until later. That said even if I am loading a big batch of 2-500 rounds, I have already got it in my mind I need to do them and this part of it has never been a chore. I simply load until i get tired, or it gets late, and come back for the rest later on.
When I went through 1K of both 30-06 and 308 surplus brass, sizing and decapping, reaming the pockets, trimming, and sorting according to head stamp and year, THAT was a chore as they all had to be sized in a SB die in order to feed through my rifles. I was NEVER so glad to be through with a project as I was with those. It sure has put the other couple of boxes I have of them WAY back on the back burner.
If I am loading up 50 or so revolver or even some pistol rounds, I usually still use the single stage as I get a much better feel for the crimp and usually a much better control on the length when seating my bullets. The progressive DOES get used however when I am loading large batches of 38, 357, 45 ACP and 10mm, the progressive get the go. I just don't feel up to handling the smaller cases in bulk.
The biggest thing is to pace yourself. I turn on the radio, to a good classic rock station and go. The music doesn't distract me and in fact it gets me into a rhythm and before I know it I am done. It's like I told my wife while we were going down the highway listening to some station, to me it is simply a noise that keep my mind alert, but other than that I really don't even pay attention to what is playing.
Mike / TX