Dry lube: how often?

Drylube in dry weather = once a week (I do about 100 - 150 miles a week)

otherwise needs lubing after every trip in the wet.

+1
Dry wax lube* = every 100 miles
Wet lube** = once a week

(*I'm currently using the white lightening stuff. Gives a good wax layer without the need to apply too much)
(**I'm currently using the TF2 extreme, and its nice a sticky)

In my experiance a good wax lube will need topping up more often in dustier the conditions (as the manufactures claim I suppose).