I have a regular, good mouse without any extra buttons and feel that I'm doing just fine using that and my regular, sturdy keyboard. Whether you want a mouse with lots of extra buttons probably depends on your playing style. If you're told to "get a 12-button mouse" to "really play at high level", I'd say you should ask yourself whether you feel that you're not doing well enough with your current equipment, but if you have no issues e.g. with your veteran dungeon healing, then why buy something you don't need?