In the past, my wife didn't give a damn about how her car looked (inside or out) so she never cleaned it and never asked me to....I mean it WAS a 1998 Dodge Neon. I took very good care of my 01 Focus on the other hand. When it came time to sell them both, I got over KBB and she got under KBB. Both ran great, but mine was impeccable.
Then we got her an Outback and she started to keep the inside clean(er) and asked me if I would clean the outside occasionally. Now she has a brand new Impreza and starts getting twitchy when she hits a puddle or the dog messes up the back. Now I wash it more than my Tacoma. She does a lot around the house and I like keeping it clean.
Jeff in Flagstaff