There's a significant difference in value between a snowbelt car and a SoCal car. If you can't figure that out, you're not looking hard enough.
There's a significant difference in perceived value between an average car with swirls and scuffs versus a car that glows like a mirror in better than new condition half a decade or more after purchase.
Of course, if you sell to a non-private party, you're accepting less to begin with, so why bother with best condition, eh?
Earlier today, I washed my car for the first time in 3 weeks as follows:
1. Foamed using a manual pump foamer, 1 gallon of water, and 0.5oz Prima Hydrowash
2. Rinsed with a car wash wand mostly at low pressure. High pressure for the rims.
3. Dried, panel by panel with quite a few microfiber towels.
During alternate weeks/periods/as necessary, I use GlassWow (a Richard Lin/Show Car Detailing product), 303 Aerospace Cleaner for black plastic and other synthetic surfaces, a lemon oil variant for the wood, and Bick 1/Bick 4 for leather cleaning or conditioning.
I also have 2 buckets, ONR, and a dirt guard (not a grit guard) for 1-2 bucket washing should I be away from a DIY car wash for the wand rinse. Oh, and a drying towel, a funnel, and a measuring cup.
All of the above fits in the frunk with room to spare.
i spend approximately as much time as I used to at the busy best full service car wash in the area waiting for variable results from a variable staff, and I will save money over time with better results. So simple.
Waiting a few minutes more for the foam to drop off:
Glass versus paint afterward - gotta love it:
One more, also from earlier today after the wash: