Stylus Warm-up Time

Do you prefer to warm up your stylus before listening i.e. by playing one side (or 2) of an "expendable" LP?

How long is considered acceptable warm up time?

Do you listen immediately or do you wait until the optimisation period is up?

Also what temperature range do you listen at? (My preference is 21-23 degrees C ambient although it doesn't mean I'll stop listening if it goes to 23.5 ;^)