Most broken scrapers I see have the same shape: someone wrote the extraction logic first and the selectors second. The selectors were an afterthought — whatever worked in DevTools at 2am.
That's backwards. Selectors are the contract between your code and the page. Get them wrong and the rest of your scraper is irrelevant.
The mindset shift
Selector-first thinking means: before you write a single line of extraction code, you decide how the data is identified. Not "how do I get the price?" but "what does the page tell me, programmatically, that this thing is a price?"
Three answers, in order of preference:
