An index-coverage decision says which URL stays published and indexed, which one merges into another, and which one comes down. It is not a ranking promise. Leaving the wrong URL in the index sends the buyer through the wrong door.
The URL that stays
A URL that stays answers one commercial question, has one canonical address and carries an enquiry step. It is not a copy of another page. Internal links point at it. Without those three, leaving it live is a habit, not a decision.
The URL that merges
A URL that opens the same intent a second time is merged. The tool can be a 301, a canonical or noindex. They do not do the same job. A 301 moves the old address to the new one. A canonical names the original of a copy. noindex says the address may stay and stay out of the index. Which one applies depends on whether buyers still use that address.
The URL that comes down
If the campaign ended, the product is gone or the office closed, the job of that URL is over. Leaving it spends crawl budget on a dead address. A redirect is for an address that still has outside links and a living intent. Not every 404 is a loss. Not every redirect is a rescue.
Coverage on a relaunch
When the site is rebuilt, the old URL list is matched to the new map. An unmatched address is not told that the ranking will hold. What can be held is a door for the question a buyer asks. If the door is gone, position is not the conversation. HED Creative writes the match. An estimated traffic percentage is not offered.
The match needs the old list, the new list, and which addresses still take enquiries. A relaunch date is not a promise of position.
Which URL stays is listed in the SEO agency scope. If the relaunch is a site job, website development is the same brief. The crawl itself: crawl budget.