Muslims are good people. They like to do good things.
And they also tell each other to do good things.
But that is where sometimes the catch is: "What are the good things that Muslims must do?"
And all of us must do?
We are talking outside all the compulsory duties of course -- the Faraa-id.
And outside all that Muslims know to be strong Sunnah.
So, the question is, in matters which involve neither direct Fard, nor strong Sunnah, what kind of good things should Muslims do?
A rude fellow like me will say:
"Trust your judgment."
"And your common sense."
"And your past experience."
"Do some cost-benefit analysis like smart people."
"See which investment is likely to produce the best and highest returns on your time, money and effort."
Better people than me, which is practically everyone else on this planet, will say:
"Hey, why don't you check out this Hadith Sharif? The one which says:
Al-Mu'minu ... Kayyisun, Fatin.
Meaning, roughly, a believer is a sharp, smart operative. He or she does not get bitten from the same hole over and over again.
Laa Yuldaghul Mu'minu Min Juhrin Waahidin Marratayin.