Open SC, go to https://www.openstreetmap.org/way/227493587 and find its address quest. I wasn't able to. Possibly because the Billa node already has an address.

Now, using Nominatim search for "бул. Черни връх 94". It finds only Billa but not the pharmacy I want to go to. The pharmacy is in the same building but it doesn't have an address. Maybe we should duplicate it?

Now look for "Златовръх 4, София", It finds everything except the payment centre (not sure why) and the insurance office (for which I've put an apparently wrong address).

You can also look for "бул. Черни връх 100". Do we have to put this address on all 100+ shops in this mall? What benefit would we get that we are not getting currently?

This is why we either:
1) put the address on every building (and on shops within if it differs from the building)
or
2) on every building and shop (but that applies to all shops of that building if the building doesn't have an address).

Which one is easier to follow and verify that it is being followed? Which one requires more time to be spent on every object?

> This cannot be an excuse not to add addresses. It is simple wrongdoing to move a node and not updating it. This contradicts the idea of OSM in my opinion.

> And again, if a shop closes, the node can simply be removed or changed to the successor. If a shop moves, of course a node must then be updated - updated location is logically also an updated address.

You are absolutely right - OSM relies on correct editing. If a shop closes or moves, updating the node (and its address) is simply part of proper mapping.

However, most of us have limited time for OSM - we map in our spare moments, between work or study. So, it makes sense to prioritise things that provide real value to end users, and leave tasks that software can infer automatically to the software while also making sure that we keep it as simple as possible to avoid some mistakes (like forgetting to update the address of the shop when we move it).

> No app in the world can find out that local rules might apply (house numbers, PO-box numbers). Therefore mappers should be encouraged to collect as much info as possible.

Actually, this rule does apply globally: add addresses where they differ, not everywhere. If local conditions mean the address truly differs from the building’s, then yes - add it explicitly. Otherwise, duplication just creates more maintenance work without improving the map. And yes, every app is capable of inferring the address from the building. Not only that but most apps do it in less than 1 second!