Honestly...IDK :) I use a cloud miner (the "blue app"), and I "invested" around $5 to buy 200+200 Gh/s power (it was a promotion for new members to get double for the same price). This purchase don't need maintenance and renewal, it is for lifetime. I earn 38 sats with that daily, so I have a ROI of 154-155 days (with a $85k BTC price). I cash out every week (with zero fees). We will see :)