Got a manilla folder for every vehicle I own, including motorcycles, dirt bikes, and the ATV.
The car ones are at the bottom. You can see my '74 RD350 folder labeled on the left - it's thick because I did a frame-up restoration on it.
The 2 super-thick & worn out ones in the middle are the '89 S10 Blazer I just sold, and my '07 Silverado. Sad how the '07 is one of the thickest ones there .. and it's the newest vehicle I own, with the least miles. Hmmmm ...
Next to the Silverado all the way to the right is the file for our '86 Grand Marquis - owned for 13 years, 3 decades old, with 4x the miles on it, and the folder is HALF as thick. Goes to show ya something there ...
On top all the way to the left (next to filing cabinet) is the folder for our '93 Volvo 940, also extremely thin. Needed a bit of work to get it road-worthy too. The folder next to that is for equipment I repaired, but don't own, so it doesn't count.
File thickness tells the tale ...