They said that the premiere will act as a 'second' pilot but I think you should check out the first season since there's some plot points tackled in s1 that you probably need to see before heading for second season. If I were asked, episodes necessary for you to watch would be the pilot (it starts a little shaky as all pilots are but with glimmers of the magnificent characterizations just underneath), third episode (beginning of the solidification of the partnership), 4th episode for the plot point in the conspiracy and the funny guest star but skippable since the previouslies can handle the plot point, 5th episode necessary for plot point *and* characterization. This is also the ep where they realize what they're fantastic with: quirky imagery, music and characters and the push-pull dynamic of the partnership. Episodes 6 to 11 are all necessary for the plot and characterization.

Honestly though, it'll all just go by fast because the episodes are fast paced, although, the crime of the week might leave you a little 'Huh?' at times because Life isn't really a cop show. It's a show about two broken people recovering from their past and not letting their tragedies define them. It has dramatic moments but it doesn't take itself seriously. Oh, and if The Mentalist interests you, Life has the same quirky, complex lead in Charlie Crews (Damian Lewis).

Also, if you're an X-Files fan the partnership will remind you of Scully and Mulder.

Erm. Sorry if I went overboard there, Life's such a small fandom that I get over excited when I encounter any interest.:)