I went to Winterhold and was turned away from the college because I didn't have enough magic. Oh well.

While I was there, Birna had an Amulet of Minor Smithing, for ~1000g (+12% armor enhancements). I didnt buy it because i was saving money for something else.

I spent the money on the wrong thing, so I decided to replay from when I first went to Winterhold, go back and buy the amulet.

When I got there, she didn't have the amulet! Turns out, she has random items in her inventory.

So the first time you go there, if you dont like what she has, revert to the save prior to when you walked into her shop. She will have different items. She has between 1-4 items it seems.

On the fifth time going in, she had an Amulet of Major Smithing (+17%) AND a Ring of Blocking (+20 block). This was winning the jackpot for me.

I'm not sure if her inventory will rotate if you leave and go back on the same thread (im guessing not), but you can certainly get what you want from her the first time you visit. Good luck.

All merchants have randomized goods based upon your level (meaning they start out with low-level equipment, and start selling high-level equipment as you level up), and will restock their inventory (and reset their total amount of gold to buy your stuff) every 2-3 days. There is, however, a bug with the game re-randomizing if you reload.

The game also does this for dungeons - you can save just before you walk into a dungeon, loot it, and if you don't like the loot, reload, and the loot will be different. The loot inside a dungeon is randomized at the time you load that cell, so if you reload before you walk into that cell, you re-randomize the loot.

There were certain dungeons in Oblivion that were favored because you could get several chests with good equipment in it fairly quickly through a side door into the dungeon. If you just kept reloading, you could get whatever loot you wanted.

Welcome to procedural game design.