First off...I'm no expert at reloading. Just IMO stuff...
I reload (current and past) 9mm/45-70/30-06/308/22-250/6ppc.
For some (i.e. 6ppc) there's no option but to handload. And since you're likely to be using "premium" components it's not cheap. There's really never a "break even" or "pay off" period.
For others, where the rounds are more plentiful...I reload for accuracy and availability of a great round for my setup. (Generalization) if you want to chase really small groups at short or long range you'll be reloading. Again...since you're obsessing over minutiae you're probably reloading with premium components and so it's about the same as factory, maybe a bit less. The cost to doing this is paying for precision and consistency.
For some, say the 9mm...factory/surplus/factory-like reloads are plentiful. But reloading is cheaper and more plentiful (disregard personal time expended). Buying 500 bullets at a time, a pound or two of powder and 1000 primers at a time (vs increased savings by buying much more at once)...my 9mm reloads come out to almost exactly half of what good quality "cheap" ammo or factory-like reloads comes out to once I figure in taxes/shipping. 100 rounds on a Dillon Square Deal takes me about 20min...that's going carefully, checking each case, measuring the odd powder charge, and not rushing.
For really expensive (to me) rounds that I like to shoot, for example 45-70, factory boxes of ammo are really hard on the wallet. For 45-70 decent ammo runs $40-45-49/20 rounds (usually $45) plus taxes. Reloading with cast bullets it's running at about 35-40% for my reloads. Still pretty expensive but at least livable. 20 rounds (from cleaning brass/deprime to final wipe and put in range box) takes 30-40 min on my single stage setup. That's going carefully, changing powder weights and weighing each charge (I'm developing loads), lots of checking. Having a set load and a smooth well organized setup and just cranking out rounds it'd be much faster...100 in well under an hour. I'd probably stop at 200 in an evening...since it'd be a while before I shot those all up.
30-06...I'm setup to reload for it. Have the dies/components...I just don't bother. I only use it for hunting and have several boxes of a certain factory load that shoots well under MOA out past 200yrds consistently. It'll take me years to use that up.
So in general I'm looking at deferring about 50% when using handloads. My reloading setup for the 9mm cost ~$450. So somewhere around 3500-4000 rounds I'll "pay for" the reloading setup.
For 45-70, the single stage press and dies weren't all that expensive so probably within 400 rounds it'll have "paid off". Any looking at the various empty boxes of factory I would have been 2/3rds of the way there if I started off reloading vs. buying factory to start.
For me, it's important to differentiate between precision ammo and plinking ammo. I'd never spend a premium amount of money or time to do up precision reloads for 7.62x39 since all it's going to be shot out of is an beater SKS...surplus by the crate is just fine. Also, for plinking at the range I'd rarely spend more than the minimum on a round to punch paper at 10yrds. For that once in a lifetime big game shot...I wouldn't care if that one round cost $$$...because I probably have huge amounts of time/money/effort already put into the hunt.
All that said...the cost of brass is probably where you'll defer the most costs. It's the only reusable part (except those who cast their own) and can usually be reused many, many times. And a lot of savings come from reloading more than one round. The costs for your powder measure, scale, bullet puller, neck trimming/chamfer, etc get spread out more if you're reloading 2+ different rounds.
