A good benchmark would be your tendency to make purchases based on emotions, and also your tendency to make impulse purchases.
I volunteered in several marketing positions for educational non-profit organizations and university clubs, and read books about marketing and advertising to try to improve at my job.
A great deal of advertising tactics rely on emotional appeal first (e.g. identifying a human need or fear–like the want to belong, the want to find a good romantic relationship, the want to save time or money, the want to look smart–then selling a product or service as a solution. Another common tactic is to reduce friction to make a purchase, to make impulse purchasing easier (e.g. one-click purchases, very visible purchase buttons). A third is to use other high-pressure or manipulative tactics (e.g. a countdown timer to get a discount, or offering free gifts or books to make a purchase).
You're likely to reduce the effectiveness of these advertising tactics on you by being aware of them (though there's a high chance they still have an effect). Besides knowledge from reading about advertising, good habits to reduce ad effectiveness include: delaying purchases, especially large ones, by writing them on a list and seeing if you still want them after a month; avoiding regular, small purchases of ~$20 because they add up; and holding yourself to a personal budget, where impulse spending comes at the cost of other life goals (e.g. setting up an emergency fund, saving to afford a vacation with a loved one, or pursuing educational training).