Keep a towel with you for the inside and outside of the windshield. The 90 miata had no HVAC or wipers and I once left someone's house an hour away at 4am.... And was wiping the re-occuring dew/moisture off almost constantly for a good 15min.So random hypothetical question(s). Say a car doesn't have A/C or heat, won't get driven between the months of October and March, and will avoid rain if at all possible. Does it serve any possible purpose on said car to retain the windshield defroster vents (and associated ducting) and/or the rear window defroster?