This seems like an uncharitable take: OP seems to be arguing you should focus on what you can measure (even if it’s personal experience), and seek guidance when you need help.
The concrete advice at the end seems pretty supported by science. Drinking and smoking are definitively bad for you.
smoking - yes, it's incontrovertible.
drinking - less clear; mortality rates for teetotallers (total abstinence) are higher than for even moderate to heavy drinkers, and there are health benefits from eg 1-2 servings of red wine. IMHO the issue is the degree to which people slip from a drink or maybe 2, to 3 or maybe 4.