Depends on the local custom. Unless instructed not to, I would read back
everything to make sure there were no mistakes in communication. Some
busy airports, such as Boston Logan request on the ATIS that you read back
only the call sign and squawk code unless there is a question.

wrote:

I flew to an FAA safety seminar tonight at Fullerton,CA KFUL.
Instrument communications. I was surprised at how little you need to
read back.

If your clearance is (I'm making this part up)

Cessna 87077 cleared to Bakersfield, via Riverside standard DP,
Paradise, dep Paradise on 270 radial, Victor 364, Pomona, as filed.
Expect 10,000 ten minutes after departure, contact Socal on 135.4,
squawk 4224.

What would you be required to readback?

Everything right? They said, "077 cleared Bakersfield, squawk 4334."

Surprised me.

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759