The practical view
A good ROAS is one that creates profitable growth after gross margin, sales costs, operational capacity, and lead quality are considered.
What to focus on
High-ticket services can tolerate very different acquisition economics than low-margin or one-time transactions. Lead-to-sale rate and average job value often matter more than the ad-platform number.
The takeaway
Work backward from contribution margin and a realistic close rate to find your break-even acquisition cost, then set the campaign target from there.