I've just got back from Italy and my first carryon only trip, so I'm quite proud of myself!
And: I still didn't wear everything I brought with me.
It was SO much easier getting on and off public transport, and lifting it up stairs and escalators; and I'm now a total carry on convert.
This is just a note to say that we flew out on Air Canada; and they did not even look at my carryon bag, let alone weigh or measure it.
Coming back was on code-share Lufthansa, and they were very strict.
First they weighed the same bag, then made me put it in the measuring box.
They said it was far too heavy and I'd have to check it.
Any shopping I had done was in my backpack, so the bag weighed no more than when I left home two weeks before.
They were very brusque, but then agreed to check my bag free of charge; so I was happy with that.
Just a warning if you are using two different airlines on the same trip.