Minecraft enchantment too expensive?

Why can't I conjure up a thorn 3 book on my chest plate (protection 4, durability 3, repair 1, thorns 1) because it is only too expensive. That's not a lot of enchantments, why is that?

You can't say that exactly. And you can't change it anyway.

It gets too expensive so you don't go to surgery. You can't do more than that.

Ok well you can't do anything

Every time you add a new enchantment to your breastplate, the enchantment becomes a few levels more expensive. At some point this value is greater than 40 and therefore automatically "too expensive" to add something.

I assume you have each enchantment up individually and only in parts, e.g. 2 times Prot3 instead of Prot4.

I agree…

Yes, you can say that exactly. There's no magic behind it.

So it's better to do it all at once

More like technology. What would you take, magic or technique?

Yes.

And if you previously Make the 2 Prot3 books into a Prot4 book, and then open that.

And if you start with the best possible books. (So don't always put level 1 together until you have a book with maximum level. Instead try to get the best possible book directly from villagers or enchanting table.

You just don't have enough XP-LVL. Go fishing, digging, or whatever to get more XP-LVL. It also says how much you need.

The more enchantments there are on a part, the more expensive it becomes, even if you often repair it, the "costs" increase.