In [What can I do to make a Kobold encounter interesting?](https://rpg.stackexchange.com/questions/188386/what-can-i-do-to-make-a-kobold-encounter-interesting/188388) there was a question of how to make an encounter more challenging.

I noted the example of Tucker's kobolds, where you lead the people to monsters, use cover, set traps, and use explosives and such and so low level people can hurt PCs.

Naut noted this.

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> How does that work when the Kobold's aren't in their lair but assaulting another structure. Yes, showing your experience with how this would work for OP is necessary. Tuckers can be a good tool, but a good answer will show how using them in this way will work and what things to look out for.
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I'm not sure exactly how to answer for this.

I've certainly used traps, sent lots of monsters at PCs, used higher damage weapons for monsters, and had enemies use cover, but I'm not sure how I'm supposed to write this as a personal experience thing.

Like, am I meant to say. "Yes, once I was playing a campaign where the level 5 PCs had to invade a goblin castle, and I had them put traps in the sewer system which caused them to take damage and find it harder, and so they had less HP left to handle the goblins in the castle, who also had a captured monster to fight which meant there were more enemies, and more enemies means a higher CR rating." Or such?

I thought it was fairly intuitive why that doing more damage or having more traps or having more monsters would be harder?

Does this apply to other questions? Like say this question about [ruby dust](https://rpg.stackexchange.com/questions/188285/what-is-a-500gp-ruby-useful-for/188288#188288) should I have added personal experience about how a player used continual flame in an encounter with rubies? What's the general rule about when to give personal experience and when not? I just gave the mathematics of what spells you could cast, just as above I just gave the sorts of mathematical ways you can make encounters harder.