If any of this was ordinary, there wouldn't be armies or castles.
I think you are quite wrong to think what you suggest is normal. If it was in the remotest bit normal in a campaign world, it would be perfectly normal to a) build all fortresses underground, b) have magical defenses that countered invisibility, illusions, and such on the approaches to the fortress.
The very fact that there is a castle barbican suggests that spider climb potions are considered rare and wonderful and not ordinary equipment.
Gabriel said:It varies and there is no standard.
Kestrel said:Love the Sig![]()
frankthedm said:In previous editions, it seemed common enough that the players brought hirelings, pack animals, torch bearers and other types of extras with them. Some might not go into “the dungeon”, but having NPCs with had some uses. Hackmaster, in a bit of gallows humor even expects the players to have these red shirts with so that when a deadly monster shows up, the players can see they are in over their heads by how fast the NPCs get cleaved trough.
But how often in 3E does this happen? Is the party just the PCs or do they hire a torchbearer [Commoner 1] with more GP than he makes in a year? Maybe a mercenary or two. A spear carrier here and there. I doubt [m]any parties would take this to the Zapp Brannigan level of sending wave after wave of NPCs at the monsters until they reached their stomach limit. But if they did, do tell.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.