[NoboruWataya]

I would go so far as to say that thinking you, as a retail investor, can correctly judge the "health" of the market shows a lack of critical thinking.

[2devnull]

Thinking that critical thinking is a specific thing (what makes one thought “critical” vs any other?) shows a lack or critical thinking. Thinking critically is not.

[BeFlatXIII]

It is equally naive to assume that a retail investor could judge which professional fund managers are scammers, which are rainmakers, and which have a real edge.

[eru]

That's why as a retail investor you put your money in low cost index funds.

It's easy to compare costs of funds: you can find them in the prospectus and the funds advertise them.

(If a fund makes it hard to find out the fees and costs, no need to sweat it: they are likely high, so you are safe avoiding that fund.)