Is marketing worth it for my business?
Yes, if you have a margin the spend can come back from and you know what one customer is worth. Marketing pays off the moment every unit of ad spend returns more revenue than your break-even point, which is one divided by your margin. At a 35% margin you need $2.90 of revenue for every $1 spent just to be level.
There are only two cases where it genuinely isn't worth it: your margin is too thin for any realistic ad performance to rescue, or you can't serve the demand you'd create. Otherwise the real question is how much and where, not whether. Performance advertising pays back in weeks, brand building in months or years, so you judge the two on different timelines.
Calculate it yourself - takes 2 minutes