For TBC PvE, a Retribution Paladin wants 9% hit to be physically hit capped against raid bosses, which is 142 hit rating. With the Precision talent, you get 3% hit from talents, so you only need 6% from gear , or about 95 hit rating.

A few common extras can lower that further:

  • Draenei group aura gives 1% hit.
  • Improved Faerie Fire gives 3% hit to the raid.

A practical rule for Ret in TBC PvE is:

  • Aim for 95 hit rating if you have Precision and no extra raid hit buffs.
  • Less is needed if your group has a Draenei or Improved Faerie Fire.
  • Extra hit above the cap is wasted for physical attacks.

Also, spell hit is not something Ret usually gears for on purpose in TBC.

Quick example

If you’re a Ret Paladin with Precision and no special hit buff, you need:

  • 142 hit rating total for the full cap.
  • 95 hit rating from gear after the talent bonus.

TL;DR: Most TBC Ret Paladins want about 95 hit rating from gear for PvE , or less if the raid gives extra hit buffs.