"Montblack" wrote in message news:3f6936c8$0$42037
I read my share of posts and this is the first time I've noticed someone
mentioning a carb temp gauge.

Is it a nice luxury, or not overly necessary?

Depends on what engine. Certain engines are much more succeptible
to carb ice. The O-300 is one. I used to fly a Cessna 170 that had one
and it would ice up in a heartbeat. Very happy it had a carb temp gauge.

Is it a standard piece of equipment on turbo's?

Dunno, all the Turbo'd aircraft I've ever flown were injected.