I hear sign it right away, then somebody else says wait until you know what it is and how you might claim. For an ordinary small ticket I just want a clear safe habit. What does the California Lottery actually tell players to do, and does the prize size change that advice?
California Lottery's current instruction is simple: always sign the back of your ticket. For an ordinary ticket that belongs only to you, sign it, keep it dry and safe, and take a clear photo of the front and back for your records. A photo does not replace the original.
Prize size does not change that basic instruction. The extra planning issue is shared ownership: California has a multiple-ownership claim process in which the group designates a representative. If a ticket was bought by a group, record the members and shares before one person handles the claim rather than treating it like a solo ticket.