Many of the pens I use fairly regularly are over a half century old, some getting close to a century old. I don't have any pens that I would not use for any writing task. They go out in my shirt pocket and get used for everything from filling out forms, signing documents to doodling.
Some that have gotten to go out and play in the last few weeks: (what good is a thread without porn? )
Let me also add a few that might be considered as going on forever that still are going strong:
the 1941 Parker "51" dad gave mom when they got engaged
the 1943 Parker Vacumatic mom gave dad when I was born
a 1950s Montblanc 144 with my dad's 1954 Bulova 23 Jewel Selfwinding
a Pre World War I Conklin Crescent