Balanced Saves (3.5e Variant Rule)
From D&D Wiki
In DnD, saves stack, so multiclass characters have a big advantage. Eg., a cleric level 1, monk level 1, would have better saves (+4,+2,+4), than a monk level 2 (+3,+3,+3), even though monks have better saves than clerics. Furthermore, a cleric level 2, fighter level 1 would have the saves +5,+0,+3, even though a fighter (which has worse saves) level 3 would have saves +3, +1, +1, which is better.
The New Way
Each level that grants a good save would equal a +1/2, and each that granted a bad save would equal +1/3. Exceptions: The level one save for good saves would be equal to +2 1/2.