Developing black-and-white film at home
Sending film to a lab was taking three weeks, so I bought a changing bag, a steel tank and a bottle of HC-110. The first roll came out thin and streaky. The fifth one was good.
What made the difference
Temperature, mostly. Keeping the developer at 20 °C with a bowl of water did more than any change in agitation. Second: loading the reel in daylight a few times with a ruined roll until it became muscle memory.
Kit list
Changing bag, stainless tank with two reels, thermometer, three measuring jugs, developer, stop bath (water works), fixer, wetting agent, and clothes pegs. Under fifty euros if you buy the tank used.