Hamilton is one of the hardest cities in Ontario on a vehicle's paint and interior. Five to six months of the year, the QEW, the Linc, the Red Hill Valley Parkway and every Mountain access are coated in road salt and liquid brine — it ends up ground into your carpets and bonded to your paint, and it doesn't come out with a drive-through wash.
The lower city adds a problem most of Ontario doesn't have: industrial fallout. Fine iron particles from the bayfront industrial corridor and rail lines settle on horizontal panels, embed in clear coat and feel like sandpaper under your hand. If you park outdoors in the north end, Crown Point or anywhere near the harbour, your paint almost certainly needs chemical decontamination and claying — not just a wash — before any wax or coating will bond.
Add escarpment gravel kicked up on the Jolley Cut and Kenilworth access, spring pollen in Dundas and Ancaster's tree-lined streets, and the humidity that rolls off Lake Ontario and breeds mildew in damp winter carpets — and an annual proper detail stops being a luxury. It's maintenance, the same as an oil change.