A/C is poor

[Converse]

My A/C is poor at cooling, when driving along the other day there was a lot of clicking (from the compressor?) every few seconds with a slight drop off in power (enough to notice). Is this normal?

[pdV6]

Any clue as to what car we're talking about?

Do you use the a/c throughout the year or just in the summer? If the latter, then the seals have a tendancy to dry out leading to the refrigerants escaping & thus poor performance.

May need to get the system re-gassed and then ensure you use it every week at least in order to keep it in tip top condition.

[wombat rick]

The 156 A/C is not great but it's OK if you leave it on full auto and don't tinker with it other than to adjust the temp. This also means it's working all the time so you don't get the problems pdV6 mentions. It tends to permeate cool air into the cabin where as sometimes you just want a big cold blast straight at your noggin.
If you've got lots of clicking it's possible that one of the direction flaps has become stuck - they are motorised and have been known to conk out. Maybe they can look at it at same time as your other error!