I was too busy to write about it when I discovered it initially.

There’s a rhyme and a reason to magic item levels in 4e — or there was — or there were some guidelines. I don’t know, anyway I found a pattern to the magic item levels beyond what I had initially assumed, yadda yadda.

If you’ve stared at the numbers long enough, you’ve probably realized that weapons, armor, and amulets all improve by +1 every five levels:

+1 1st-5th
+2 6th-10th
+3 11th-15th
+4 16th-20th
+5 21st-25th
+6 26th-30th

What may not have made sense — is the rest of the system. Sure, enhancement bonuses increase every five levels but what does any of that mean? Your attack and damage bonuses go up, but all the good stuff is 2-3 levels beyond that.

There is a simple guideline — which isn’t strictly adhered to but is present nonetheless — that adding one trait or property to a magic item increases its level requirement by two, and adding two properties increases it by four.

And that’s how you get 3rd-/5th- and 8th-/10th-level items.

“But what about 2nd-/4th- and 7th-/9th-level items?” There’s a straightforward answer to that — the “rarity” of magic items, introduced retroactively in Mordenkainen’s Magnificent Emporium, helps explain some of the discrepancies. The above accounting is for “common” magic items.

By increasing a magic item’s rarity to uncommon or rare, you artificially reduce level requirements by restricting accessibility to the item via crafting rituals. My estimates are -1 for uncommon and -2 for rare, but these need verification.

You could add properties to uncommon/rare items instead of reducing level.

It’s worth noting that the above guidelines are for weapons, armor, and amulets. The rest of magic items — including but not limited to boots, belts, bracers & shields, helmets, gloves, and rings — follow slightly different guidelines.

For the time being, I can’t do more than speculate on the level requirements for “non-essential” items, and the most I can figure is they start a minimum of one level higher than weapons, armor, and amulets.