How hard is it to replace all motor mounts on a 2005 Avalon. on 2005 Toyota Avalon

I have 2005 avalon with 180,000 miles on it. I was told by shop that I should replace the motor mounts . How hard , or much skill level does it take to do this job ? Is this something that I could do with basic tools? Could I use after market mounts (OEM replacments) or should I use Totota parts ( very expensive) ? How can you tell if one or all mounts need to be replaced ? Thanks

Asked by for the 2005 Toyota Avalon