Based on the current numbers, it appears that California may have more new legislators in 2013 than it has seen in nearly a century. There are 120 inumbent state legislators, of whom 29 will be terming out this year;

7 State Senators; Alquist, Calderon, Dutton, Harman, Kehoe, Lowenthal, Simitian

22 Assemblymembers; Beall, Calderon, Cedillo, Cook, Davis, Eng, Feuer, Fuentes, Garrick, Huffman, Jeffries, Mendoza, Brownley, Portantino, Carter, Galgiani, Hayashi, Ma, Silva, Smyth, Solorio, Swanson

Additionally, a large number are running for other offices;

Congress; At least three Senators (Blakeslee, Negrete McLeod, and Vargas) and three Assemblymembers (Hall, Hernandez, and Miller), possibly also Assemblymembers Torres and Valadao. [Source]

State Senate (Block, Fong, Monning, Perez (V.M.), Harkey, Lowenthal, Williams)

Mayor; Senator Yee (San Francisco), Assemblyman Fletcher (San Diego)

Redistricting. Finally, redistricting has impacted several seats, either changing them to favor the other party (Huber, Gorell) or placing multiple incumbents in the same district (Dickinson vs. Pan, Strickland vs. Pavley)

RECORD-SETTING LEGISLATOR TURN-OVER
This brings the total number of new legislators to somewhere in the range of 40 to 50. The election of 43 new legislators would set the record for turnover going back to 1935, while reaching a total of 50 would tie for the most since 1917.