OV-103. The space shuttle Discovery. Twenty-seven years of service. Thirty-nine times it lifted off and thirty-nine times it landed safely. All told it spend a year in space and traveled over 238 million km (148 million miles). That sort of use leaves its mark after a while.
Here’s Discovery on its first landing in 1984 (STS-41D). Look how bright the upper tiles are (there’s a little heat smudging) and how evenly dark the bottom tiles are. It’s nice to be new.
And Discovery’s 39th landing in 2011 (STS-133). Though the orbiter had been cleaned a few times over the years, the upper tiles have definitely seen some heat. The bottom tiles have lightened from fiery re-entries and gotten mottled from tile replacements. This is a ship isn’t going to surprise you. Experience matters.