Yes I have failed at #1 and #6
I have purchased stuff failing the #1 rule.
OFTEN.
I just want to try it out anyway.
Sometimes there are not even any reviews!! (the Audio research PH-2 was one such box I bought. I still have it and enjoy it.I watch for it and have only seen three here offered, and one of those I bought!)
Most of the time I have been happy with the item. Once I made a lot of money doing it(ARC SP-10), and another time i was unhappy and pissed about it, but WAS able to return it to dealer.(Bryston DAC)
For #6 I did it, and have to say I was young and stupid at the time.
The biggest things on turntable blunders are missing counterweight, or missing headshell. Run not walk away. (unless a universal headshell mountwhere you already have a headshell you have tried and it fits!!!)
A corollary of that is do not buy a non fully functional auto return turrntable!
My own Waterloo was buying two separate Garrard-LAB100 P.O.S. TTs to play around. (pretty much dirt cheap) They were soon tossed into a dumpster.
In thier infinite wisdom, With the LAB100 Garrard decided to make a product where if two parts together were good, 17 Rube-Goldbergesque were better. And they proved they were idiots with that design. Lucky for them the buyers spoke and they folded. What horrors they would have come up with if they had be able to continue.. I shudder...
So I admit I am not perfect either.
And my breaking one of my own rules?
LOL