Expert 9mm Questions?

I just purchased an Expert in 9mm. I'm primarily using this as my bed side gun and the occasional range toy until I land the USP SD. What's the recommended ammo for the range and home defense? I'm thinking +P Critical Defense for home defense and normal cheap ball ammo for the range. If I choose to shoot +P at the range to get familiar with the gun, will it shorten the life of the factory recoil spring? Should I purchase a factory USP Standard or Tactical guide rod assembly to use instead of the factory Expert one?

Also, I'm somewhat new to the 9mm round. Making the change from .45 acp. I figure with todays ballistic technology and round capacity, why not..

Thanks in advance..