Equipment and electricity?
I haven't bought anything that wouldn't pay itself off in 6 months or less but as ETH has been booming I'm closer to 90 days or less ROI on anything I bought specifically for ETH mining. I haven't bought anything from a scalper and I haven't scalped anything.
I have spent a decent amount to get into Chia farming and have not gotten any return yet.
My electric bill is about $80 more a month and I'm currently projected to earn $2559/month gross, although that fluctuates quite a bit.
Keep in mind that my three biggest earners for ETH mining are the GPUs in gaming PCs that get used as gaming PCs (one of which I'm using to type this message). I have bought stuff sooner than I would have without mining, but I've had relatively high end gaming PCs for the majority of my life. If mining went away today I would keep all of my current generations equipment and be perfectly happy about it.
Good stuff - you keeping your rig in the basement or a dedicated space away from everyone? I have a neighbor who is trying to get in the crypto game and wants to take a 20 x 15 unfinished room in his basement, soundproof it and fill it with some stuff. My advice to him is that you either go all in or do nothing at all; otherwise, you're just wasting your time.
I think you're smart to sell vs. holding on - I know many would say hold the long and keep it like any investment, but I think you're definitely better off turning it liquid vs. the risk as you're still getting a sizable return and the marketplace is pretty ridiculous when the word of one eccentric guy can send it to the dumps. Even if you decided to walk away, you could sell your equipment for a nice bundle as well.