In reply to SARS:
I go against convention, wear all of my clothes in the walk in, go fast in the walk in ( and early) to beat the crowds, gear up and stick a hat on to keep warm, then climb all day like that with hat on under my helmet
All my clothes are somewhat minimal to what others wear but it works for me, only emergency clothing is perhaps a goretex if it has not been worn on the walk in ( if it is dry and not blowing a hoolie )
Belay jackets just equal faff and time wasting