I definitely differ strategies on my serve and return games.
I believe a player is only as good as their weakest service game. It doesn't matter if you win most service games at love if you occasionally have a miserable one. Therefore I play more conservatively on my service games so that there is less variance between my weakest and strongest service games.
Along those same lines, many times you only need one break to win a set, so I go much bigger on my return games. It doesn't matter if I lose most return games because of errors, if I have at least one game each set where it all comes together.