I volunteer 1 day a week at a butcher shop except during the busiest part of the farm season (non-USDA) - Used to do more, but can't anymore. Have learned a lot over the past several years.
For example, You don't "have to" hang beef, but it does taste much better if you do. Big corporate shops (Tyson, etc - what you get in stores) typically don't hang meat, they wet age it - vac pack primals while fresh and let it soak in the blood till it gets to the store where it gets cut into steaks, roasts etc.
The other thing I've learned is that hanging more than 10-12 days is really a waste. At around 7-10 days the fat is firm, blood has dried and/or redistributed back into muscle and the meat hasn't started to mold. Letting it hang 3 weeks + (what most big city folk say they have to get) causes a lot of exterior mold that has to be cut off and trashed (making yield much less - anywhere from 10-30# of meat in the trash).
One of the side benefits I get from helping them out is that I only get charged for supply costs when I get things processed - vac bags, spices (sausages, ham etc), etc. For me it's a win, win situation I learn, help him out and get almost free processing. During COVID when Tyson was shut down, the shop was able to get pigs from Nebraska off the feed lots delivered down here in AR for $150 ea because they got to big for Tysons equipment. I bought two, processed them and not have a 29 ft3 chest freezer full of pig (one was nothing but sausages (country & Italian), grind & smoke (ham, bacon,picnic etc) the other was mostly chops, roasts ribs etc - of course the hams & bacon and any scraps went to more sausage. All total (less the cost of another chest freezer), the two pigs cost me ~$350 and should last the wife & I about 2 years. One of our cows just got processed that filled another 29 ft3 chest and that cost me ~$100 in processing fees. Not bad for 2-2 1/2 years of prime quality meat. Once a year we process a lamb (around easter) at the shop. I've also learned how NOT to mangle my deer, another added advantage. For chicken, we still process that ourself as we need it he only processes 4 legged farm critters & deer.
You'll have fun (if you like to learn), it can be hard work (especially in the kill room), and typically shops will let you in on some of the perks.