Finally for the $3 or so you might really make per month, you are not taking into account the depreciation of your rigs. You proudly claim my "rigs are paid off" then go on to tell us how clever you are with making a few bucks a month with that equipment. What you fail to account for is that your rigs have value on the resale market and this value goes down each day.
I don't agree with this at the current moment. Basically we pretty much had a crypto crash and many are dumping their GPUs all over eBay and on Craigslist. The prices for mining equipment at the moment is very low. He is basically better off selling the equipment in 6-12 months or so when the supply has been absorbed or "maybe" mining is a little more profitable again.
An RX 470 4GB is going for maybe $70 today, in 6 months it'll maybe go for $100 and maybe in 1 year start depreciating again down to $70. In other words you are better off not selling anything and also not mining either.
This is true. Look at the price dump the 1080Ti experienced. Market overreacted and they went back to $5xx area for a few days, then the shitty 2080 results came out and the 1080Ti prices went up again. But flagship level cards are always deviants.
There are 2 advantages to be considered selling now though. The demand is there from Christmas shoppers so it's a lot easier to sell. The second, and probably more important point, is that selling now will free up funds should crypto go on a firesale. I always like having a standing buy order just in case somebody Fat Fingers a massive sell - it paid off well when BTC got fat fingered to $104 (I think that's the price it hit on BTCe).
Having money now in hand allows for opportunities that may otherwise be missed. Man if I used my med school tuition debt and instead bought 2 houses in Southern California and flipped them just 2 years later I would have made $1 million and would only be taxed on $500k. I could have then bought again in the 2011 dump and made about $4 million at current prices. Sadly I have not come anywhere near that from my sad medical career.
But if you're only playing the mining game it makes no sense selling now other than being able to quickly liquidate to holiday buyers.